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Following the continuous development of wide bandgap (WBG) devices and multilevel converter technology, medium voltage (MV) active front ends (AFEs) are becoming promising in future high-power-density and high-power applications. However, the cost issue is one of the major drawbacks, which stops the WBG devices from being widely applied in high-power areas. This paper proposes a silicon carbide (SiC) and silicon (Si) hybrid five-level unidirectional rectifier. It requires only four SiC MOSFETs with relatively low blocking voltage and four Si diodes. Meanwhile, by adding snubber capacitors, all the Si devices are with low-speed switching, and the voltage stresses of fast SiC MOSFETs are minimized. In this paper, operational analysis and carrier-based phase-disposition PWM scheme for this circuit are discussed in detail. The capacitor voltage balancing and unity power factor are both realized. Simulation and scaled-down experimental results are demonstrated to verify the proposed rectifier. Furthermore, the comparison of the hybrid five-level rectifiers is given to show the advantages of the proposed rectifier in terms of voltage stress, efficiency, and cost.
Yifan Zhang; Chushan Li; Chengmin Li; Zhen Xin; Runtian Chen; Wuhua Li; Xiangning He; Hao Ma. A SiC and Si Hybrid Five-Level Unidirectional Rectifier for Medium Voltage Applications. IEEE Transactions on Industrial Electronics 2021, PP, 1 -1.
AMA StyleYifan Zhang, Chushan Li, Chengmin Li, Zhen Xin, Runtian Chen, Wuhua Li, Xiangning He, Hao Ma. A SiC and Si Hybrid Five-Level Unidirectional Rectifier for Medium Voltage Applications. IEEE Transactions on Industrial Electronics. 2021; PP (99):1-1.
Chicago/Turabian StyleYifan Zhang; Chushan Li; Chengmin Li; Zhen Xin; Runtian Chen; Wuhua Li; Xiangning He; Hao Ma. 2021. "A SiC and Si Hybrid Five-Level Unidirectional Rectifier for Medium Voltage Applications." IEEE Transactions on Industrial Electronics PP, no. 99: 1-1.
This paper proposes a current path tracking approach that uses a current path state to correlate device status and operating mode of an inverter under normal and abnormal conditions. Based on graph theory, a node-path modeling method is proposed and applied in the T-type inverter topologies. The model reflects system state transitions given healthy or faulted transistors. Effective conduction paths and node potentials can be derived with the model to indicate circuit faults. In addition, a hierarchical diagnosis method is proposed for single-transistor open-circuit (OC) faults, based on estimated output voltage vectors. The diagnosis involves two steps. First, an OC fault can be detected by following a residual between an actual voltage vector and its reference voltage vector calculated from duty ratios of intended current paths. Next, faulty transistors sharing similar features can be distinguished by adopting a current path state reconfiguration approach. Diagnosis variables can be obtained from the controller, and their errors because of sampling, signal delay, and dead time are taken into account to avoid misdiagnosis. Experimental results verify the robustness and effectiveness of the proposed method.
Borong Wang; Zhan Li; Zhihong Bai; Philip T. Krein; Hao Ma. A Voltage Vector Residual Estimation Method Based on Current Path Tracking for T-Type Inverter Open-Circuit Fault Diagnosis. IEEE Transactions on Power Electronics 2021, 36, 13460 -13477.
AMA StyleBorong Wang, Zhan Li, Zhihong Bai, Philip T. Krein, Hao Ma. A Voltage Vector Residual Estimation Method Based on Current Path Tracking for T-Type Inverter Open-Circuit Fault Diagnosis. IEEE Transactions on Power Electronics. 2021; 36 (12):13460-13477.
Chicago/Turabian StyleBorong Wang; Zhan Li; Zhihong Bai; Philip T. Krein; Hao Ma. 2021. "A Voltage Vector Residual Estimation Method Based on Current Path Tracking for T-Type Inverter Open-Circuit Fault Diagnosis." IEEE Transactions on Power Electronics 36, no. 12: 13460-13477.
In inductive power transfer systems, misalignment and wide load range can lead to high current and control complexity. This can affect the performance of high-power systems. In this paper, a method to minimize converter and primary resonant circuit currents based on an asymmetrical factor is proposed to improve inductive power transfer system performance over wide misalignment and load ranges. The proposed asymmetrical factor incorporates two design variables: an asymmetrical voltage factor and an asymmetrical compensation factor. These help to minimize current from two perspectives. First, they tend to redistribute zeroes and poles for power vs. frequency characteristics. The power characteristic can be asymmetrical and monotonic over the working switching frequency range. Second, the input impedance angle can become insensitive to coupling factor and to load by adjusting the frequency that corresponds to the minimum input impedance angle. The current increases by only 15% over a 2:1 coupling coefficient variation range at rated load. Analysis and design guidelines are presented for the proposed method. A 2.1 kW prototype has been prepared to verify the approach.
Zirui Yao; Junjie Zhang; Shiying Luo; Zhongbao Luo; Shaoting Zheng; Guanxi Li; Zhuhaobo Zhang; Philip T. Krein; Hao Ma. Minimizing Current in Inductive Power Transfer Systems with an Asymmetrical Factor for Misalignment Tolerance and Wide Load Range. IEEE Transactions on Power Electronics 2021, PP, 1 -1.
AMA StyleZirui Yao, Junjie Zhang, Shiying Luo, Zhongbao Luo, Shaoting Zheng, Guanxi Li, Zhuhaobo Zhang, Philip T. Krein, Hao Ma. Minimizing Current in Inductive Power Transfer Systems with an Asymmetrical Factor for Misalignment Tolerance and Wide Load Range. IEEE Transactions on Power Electronics. 2021; PP (99):1-1.
Chicago/Turabian StyleZirui Yao; Junjie Zhang; Shiying Luo; Zhongbao Luo; Shaoting Zheng; Guanxi Li; Zhuhaobo Zhang; Philip T. Krein; Hao Ma. 2021. "Minimizing Current in Inductive Power Transfer Systems with an Asymmetrical Factor for Misalignment Tolerance and Wide Load Range." IEEE Transactions on Power Electronics PP, no. 99: 1-1.
This paper proposes a multi-objective efficiency optimization method for triple-phase-shift (TPS) control of isolated dual active bridge converters (DABs). A comprehensive optimization of inductor current stress, inductor RMS current and zero-voltage switching (ZVS) is presented to reduce conduction losses, magnetic losses and switching losses. A genetic algorithm is used to search for optimal solutions of the DAB non-convex optimization problem. Analysis of these solutions gives rise to closed-form expressions for optimum TPS control angles, valid over various power and voltage levels. These can be realized for real-time operation. A 3.3 kW experimental prototype is used to verify the proposed optimized modulation control.
Lu Zhou; Yihan Gao; Hao Ma; Philip T. Krein. Wide-Load Range Multiobjective Efficiency Optimization Produces Closed-Form Control Solutions for Dual Active Bridge Converter. IEEE Transactions on Power Electronics 2021, 36, 8612 -8616.
AMA StyleLu Zhou, Yihan Gao, Hao Ma, Philip T. Krein. Wide-Load Range Multiobjective Efficiency Optimization Produces Closed-Form Control Solutions for Dual Active Bridge Converter. IEEE Transactions on Power Electronics. 2021; 36 (8):8612-8616.
Chicago/Turabian StyleLu Zhou; Yihan Gao; Hao Ma; Philip T. Krein. 2021. "Wide-Load Range Multiobjective Efficiency Optimization Produces Closed-Form Control Solutions for Dual Active Bridge Converter." IEEE Transactions on Power Electronics 36, no. 8: 8612-8616.
Due to the galvanic isolation and excellent bidirectional power transfer capacity, the symmetrical CLLC resonant DC transformer has received increasing attention and been popularly adopted in DC microgrid. However, for good comprehensive performance, there are some concerns in the design of CLLC resonant DCT. Firstly, when it operates individually, its voltage transfer ratio (VTR) is hard to maintain within an acceptable range when fluctuations of inductance or capacitance exist in practice. Secondly, when the CLLC resonant DCT operates in a cascaded system with a constant power load (CPL), impedance interactions may result in instability phenomenon. The fluctuations of inductance or capacitance will also affect the stability of this cascaded system. In order to deal with these concerns, a parameter design approach for the CLLC resonant DCT is put forward by this paper. Particle swarm optimization (PSO) algorithm is specially applied to realize thorough considerations of unpredictable parameter fluctuations. Thus, the designed CLLC resonant DCT is able to maintain robust VTR and system stability when circuit parameter fluctuations exist. In the end of this paper, a 1kW prototype has proved the validity of this proposed design approach.
Fanfan Lin; Xin Zhang; Xinze Li; Hao Ma; Chunwei Cai. Design of Symmetrical CLLC Resonant DC Transformer Considering Voltage Transfer Ratio and Cascaded System Stability. IEEE Transactions on Industrial Electronics 2021, PP, 1 -1.
AMA StyleFanfan Lin, Xin Zhang, Xinze Li, Hao Ma, Chunwei Cai. Design of Symmetrical CLLC Resonant DC Transformer Considering Voltage Transfer Ratio and Cascaded System Stability. IEEE Transactions on Industrial Electronics. 2021; PP (99):1-1.
Chicago/Turabian StyleFanfan Lin; Xin Zhang; Xinze Li; Hao Ma; Chunwei Cai. 2021. "Design of Symmetrical CLLC Resonant DC Transformer Considering Voltage Transfer Ratio and Cascaded System Stability." IEEE Transactions on Industrial Electronics PP, no. 99: 1-1.
The application of wireless power transfer technology in the underwater environment proposes both opportunities and challenges to undersea power feeding. Due to the attenuation of electromagnetic waves in seawater, the distance between transmitter and receiver is always maintained at a minimum value, which results in tight coupling between the transmitter and receiver. The tight coupling condition provides a low impedance loop for high-order harmonic, so the component of the harmonic wave is thus significantly increased and cannot be ignored in the power transmission system. In order to fully utilize the harmonic energy, a fundamental-harmonic dual-channel system was proposed and studied in this paper. Compared with single-channel systems transmitting fundamental wave only, the dual-channel system has higher power transmission capability, while the loss in dual channel system can be less than that of a single-channel system after proper optimization. A 3 kW experiment platform is established to verify the effectiveness of theoretical analysis.
Jing Zhou; Pengzhi Yao; Rui He; Kan Guo; Yao Zhang; Hao Ma. Dual Resonant Frequency Inductive Power Transfer in an Underwater Tight Coupling System. Energies 2021, 14, 242 .
AMA StyleJing Zhou, Pengzhi Yao, Rui He, Kan Guo, Yao Zhang, Hao Ma. Dual Resonant Frequency Inductive Power Transfer in an Underwater Tight Coupling System. Energies. 2021; 14 (1):242.
Chicago/Turabian StyleJing Zhou; Pengzhi Yao; Rui He; Kan Guo; Yao Zhang; Hao Ma. 2021. "Dual Resonant Frequency Inductive Power Transfer in an Underwater Tight Coupling System." Energies 14, no. 1: 242.
Inductive power transfer (IPT) technology uses large resonant inductors as compensation components. In this paper, a spatially nested magnetic integration method is proposed to integrate discrete inductors into an IPT transformer structure. Unipolar transformer coils are employed and are decoupled orthogonally from a nested solenoidal inductance coil for various misalignment cases. Variations of the coupling coefficients and the magnetic flux density distribution are presented with a 3D finite element modeling (FEM) tool. An LCC series compensation circuit is selected to implement the proposed method with an optimal efficiency design. A 4 kW prototype with a 160 mm air gap is implemented to demonstrate the validity of the proposed method. Experimental results show that the compact structure retains outstanding performance and avoids significant cross coupling for lateral, vertical, and axial misalignment. The maximum conversion efficiency of the proposed system is 96.7% at full output power and stays above 91.6% throughout the misalignment range.
Zhuhaobo Zhang; Shaoting Zheng; Zirui Yao; Dehong Mark Xu; Philip Gae T. Krein; Hao Ma. Analysis, Design, and Implementation of a Spatially Nested Magnetic Integration Method for Inductive Power Transfer Systems. IEEE Transactions on Power Electronics 2020, 36, 7537 -7549.
AMA StyleZhuhaobo Zhang, Shaoting Zheng, Zirui Yao, Dehong Mark Xu, Philip Gae T. Krein, Hao Ma. Analysis, Design, and Implementation of a Spatially Nested Magnetic Integration Method for Inductive Power Transfer Systems. IEEE Transactions on Power Electronics. 2020; 36 (7):7537-7549.
Chicago/Turabian StyleZhuhaobo Zhang; Shaoting Zheng; Zirui Yao; Dehong Mark Xu; Philip Gae T. Krein; Hao Ma. 2020. "Analysis, Design, and Implementation of a Spatially Nested Magnetic Integration Method for Inductive Power Transfer Systems." IEEE Transactions on Power Electronics 36, no. 7: 7537-7549.
An inductively coupled wireless power transfer system is proposed in this paper, which is designed to comply with the battery’s load characteristics. A loosely coupled transformer with high coupling coefficient is proposed. A heterogeneous compensation topology is proposed which is able to switch between constant current and constant voltage output mode according to the load resistance. The output characteristic curve agrees with the charging curve of the battery in a whole cycle. The proposed topology has a misalignment range of 300 mm where the coupling coefficient is 0.2. A 3 kW experimental platform is established to verify the theoretical analysis, and the experimental results show that the proposed loosely coupled transformer has high coupling coefficient and high power transmission efficiency (95.2% in aligned position) within a large misalignment range, which agrees with the charging scenario of the electric vehicle.
Jing Zhou; Pengzhi Yao; Kan Guo; Pengju Cao; Yao Zhang; Hao Ma. A Heterogeneous Inductive Power Transfer System for Electric Vehicles with Spontaneous Constant Current and Constant Voltage Output Features. Electronics 2020, 9, 1978 .
AMA StyleJing Zhou, Pengzhi Yao, Kan Guo, Pengju Cao, Yao Zhang, Hao Ma. A Heterogeneous Inductive Power Transfer System for Electric Vehicles with Spontaneous Constant Current and Constant Voltage Output Features. Electronics. 2020; 9 (11):1978.
Chicago/Turabian StyleJing Zhou; Pengzhi Yao; Kan Guo; Pengju Cao; Yao Zhang; Hao Ma. 2020. "A Heterogeneous Inductive Power Transfer System for Electric Vehicles with Spontaneous Constant Current and Constant Voltage Output Features." Electronics 9, no. 11: 1978.
To charge the battery of electric vehicles (EVs), inductive power transfer (IPT) system has been considered to be more appropriate than traditional plug-in system especially for its security and convenience. This study proposes a hybrid IPT system for EVs charging applications adopting one transmitter coil with series compensation and two receiver coils with series compensation and LCL compensation. With the help of the two receiver coils and proper parameters design, the proposed system can naturally obtain constant current (CC) and constant voltage (CV) outputs and the maximum output power can be naturally limited which can prevent the system from possible overload. Therefore, the reliability of the proposed system is increased. Since the mode switching process can be automatically realised according to the value of battery equivalent load without extra control strategy and circuit, the fixed-frequency control can be used. Therefore, not only zero phase angle condition, but also the soft switching can be achieved. The theoretical analysis is presented with the design process of the IPT coils and resonance parameters for required battery charging profile. The performance of the system is verified by a 3.3 kW experimental prototype. The experimental results coincide well with the theoretical analysis.
Guanxi Li; Hao Ma. Hybrid IPT system with natural CC–CV output characteristics for EVs battery charging applications. IET Power Electronics 2020, 13, 3734 -3743.
AMA StyleGuanxi Li, Hao Ma. Hybrid IPT system with natural CC–CV output characteristics for EVs battery charging applications. IET Power Electronics. 2020; 13 (16):3734-3743.
Chicago/Turabian StyleGuanxi Li; Hao Ma. 2020. "Hybrid IPT system with natural CC–CV output characteristics for EVs battery charging applications." IET Power Electronics 13, no. 16: 3734-3743.
To combine the advantages of both model-driven and data-driven methods, this paper proposes a model-data-hybrid-driven (MDHD) method to diagnose open-switch faults in power converters. This idea is based on the explicit analytical model of converters and the learning capability of artificial neural network (ANN). The process of the method is divided into two parts: offline model analysis and learning, and online fault diagnosis. For both parts, model-driven and data-driven are combined. With the model information and data-based learning capability, a fast diagnosis for various operating conditions can be achieved without high computation burden, tricky threshold selection and complex rulemaking. This can greatly contribute to the practical application. The open-switch fault diagnosis in a two-level three-phase converter is studied for method validation. For this converter, an ANN is trained with two input elements, seven output elements, and two neurons in the hidden layer. Experimental results are given to demonstrate good performance.
Zhan Li; Yuan Gao; Xin Zhang; Borong Wang; Hao Ma. A Model-Data-Hybrid-Driven Diagnosis Method for Open-Switch Faults in Power Converters. IEEE Transactions on Power Electronics 2020, 36, 4965 -4970.
AMA StyleZhan Li, Yuan Gao, Xin Zhang, Borong Wang, Hao Ma. A Model-Data-Hybrid-Driven Diagnosis Method for Open-Switch Faults in Power Converters. IEEE Transactions on Power Electronics. 2020; 36 (5):4965-4970.
Chicago/Turabian StyleZhan Li; Yuan Gao; Xin Zhang; Borong Wang; Hao Ma. 2020. "A Model-Data-Hybrid-Driven Diagnosis Method for Open-Switch Faults in Power Converters." IEEE Transactions on Power Electronics 36, no. 5: 4965-4970.
Existed Lyapunov-based control methods for stand-alone inverters either have a single control loop accompanied with steady-state errors, or dual control loops at the sacrifice of negative definiteness of the derivative of the Lyapunov function. Besides, load-current sensors or observers are indispensable in these methods. Proposed Lyapunov-based control inherently has dual control loops that can rigorously guarantee the global large-signal stability of the system. Meanwhile, load disturbance is suppressed adaptively without any load-current sensors or observers. Stability analysis proves that the proposed method is valid both for a linear and nonlinear load. The proposed approach complies with the internal model principle, leading to the minimized steady-state error. An adaptive weighted Lyapunov function (V) is proposed to derive the dual-loop control law and adaptive law. The closed-loop system is inherently d-q decoupled. Three controller gains are tuned quantitatively via explicit formulas based on pole-placement strategy. Simulation and experimental results demonstrate that the proposed method has good steady-state and dynamic performance with great robustness against the parametric mismatch.
Jinsong He; Xin Zhang; Hao Ma; Chunwei Cai. Lyapunov-Based Large-Signal Control of Three-Phase Stand-Alone Inverters With Inherent Dual Control Loops and Load Disturbance Adaptivity. IEEE Transactions on Industrial Electronics 2020, 68, 8391 -8401.
AMA StyleJinsong He, Xin Zhang, Hao Ma, Chunwei Cai. Lyapunov-Based Large-Signal Control of Three-Phase Stand-Alone Inverters With Inherent Dual Control Loops and Load Disturbance Adaptivity. IEEE Transactions on Industrial Electronics. 2020; 68 (9):8391-8401.
Chicago/Turabian StyleJinsong He; Xin Zhang; Hao Ma; Chunwei Cai. 2020. "Lyapunov-Based Large-Signal Control of Three-Phase Stand-Alone Inverters With Inherent Dual Control Loops and Load Disturbance Adaptivity." IEEE Transactions on Industrial Electronics 68, no. 9: 8391-8401.
Inductive power transfer (IPT) technology is attractive for electric vehicle (EV) charging because of safe, flexible, and convenient features. In this paper, an integrated IPT system design employing variable inductor control is proposed to achieve a target constant current (CC) and constant voltage (CV) battery charging profile with misalignment tolerance. The system is implemented under a fixed switching frequency in both CC and CV modes. Soft switching of the primary inverter can be achieved over the entire charging process and allowed misalignment range without additional switches or dc-dc converters. Theoretical circuit analysis and the system design process are presented. A 3.3 kW prototype is implemented with a 210 mm air gap to demonstrate the validity of the proposed method. Experimental results show that the target CC and CV charging profile can be achieved by adjusting the variable inductor with up to 120 mm of lateral and 300 mm of vertical misalignment. The maximum efficiency of the proposed system is 96.1% at full output power and it stays above 95% throughout CC operation.
Zhuhaobo Zhang; Fan Zhu; Dehong Xu; Philip T. Krein; Hao Ma. An Integrated Inductive Power Transfer System Design With a Variable Inductor for Misalignment Tolerance and Battery Charging Applications. IEEE Transactions on Power Electronics 2020, 35, 11544 -11556.
AMA StyleZhuhaobo Zhang, Fan Zhu, Dehong Xu, Philip T. Krein, Hao Ma. An Integrated Inductive Power Transfer System Design With a Variable Inductor for Misalignment Tolerance and Battery Charging Applications. IEEE Transactions on Power Electronics. 2020; 35 (11):11544-11556.
Chicago/Turabian StyleZhuhaobo Zhang; Fan Zhu; Dehong Xu; Philip T. Krein; Hao Ma. 2020. "An Integrated Inductive Power Transfer System Design With a Variable Inductor for Misalignment Tolerance and Battery Charging Applications." IEEE Transactions on Power Electronics 35, no. 11: 11544-11556.
Higher-voltage-standard and higher-power-rating aerospace power systems are being investigated intensively in the aerospace industry to address challenges in terms of improving emissions, fuel economy, and also cost. Multilevel converter topologies become attractive because of their higher efficiency under high-voltage and high-switching-frequency conditions. In this paper, an asymmetrical-voltage-level back-to-back multilevel converter is proposed, which consists of a five-level (5L) rectifier stage and a three-level (3L) inverter stage. Based on the comparison, such an asymmetrical back-to-back structure can achieve high efficiency and minimize the converter weight on both rectifier and inverter sides. A compact triple-surface-mounted heatsink structure is designed to realize high density and manufacturable thermal management. This topology and structure are evaluated with a full-rating prototype. According to the evaluation, the achieved power density is 2.61 kVA/kg, which is 30% higher than that of traditional solutions. The efficiency at the rated power of the back-to-back system is 95.8%.
Yifan Zhang; Chushan Li; David Xu; Wuhua Li; Jian Zhang; Hao Ma; Xiangning He. An Extremely High Power Density Asymmetrical Back-to-Back Converter for Aerospace Motor Drive Applications. Energies 2020, 13, 1292 .
AMA StyleYifan Zhang, Chushan Li, David Xu, Wuhua Li, Jian Zhang, Hao Ma, Xiangning He. An Extremely High Power Density Asymmetrical Back-to-Back Converter for Aerospace Motor Drive Applications. Energies. 2020; 13 (5):1292.
Chicago/Turabian StyleYifan Zhang; Chushan Li; David Xu; Wuhua Li; Jian Zhang; Hao Ma; Xiangning He. 2020. "An Extremely High Power Density Asymmetrical Back-to-Back Converter for Aerospace Motor Drive Applications." Energies 13, no. 5: 1292.
The system performances can be potentially enhanced for three-phase inverter parallel operation in droop-controlled AC microgrid by using network-based control, which also benefits for the extension of other control strategies in microgrids (MGs). It is highlighted that some negative factors such as network-induced time-delays and data dropouts would possibly degrade the system operation. In this paper, the comprehensive analysis of network-based control strategy with strong robustness and wide time-scale compatibility is investigated in islanded mode of an AC microgrid with paralleled inverters. The theoretical evaluation towards time-delay and data dropouts is made and it is verified that its good power-sharing can be obtained under unsatisfactory communication conditions. It has been observed that the time-scale of network-based control can also be designed from several microseconds to milliseconds. Based on this idea, the communication integration of different layers of MGs in hierarchical structure would be realistic. Experimental results have verified the effectiveness of the network-based control strategy and analytical method.
Yao Zhang; Fan Zhang; Yu Quan; Pengfei Zhang. Analysis of Three-Phase Inverter Parallel Operation with Network-Based Control Having Strong Robustness and Wide Time-Scale Compatibility in Droop-Controlled AC Microgrid. Electronics 2020, 9, 376 .
AMA StyleYao Zhang, Fan Zhang, Yu Quan, Pengfei Zhang. Analysis of Three-Phase Inverter Parallel Operation with Network-Based Control Having Strong Robustness and Wide Time-Scale Compatibility in Droop-Controlled AC Microgrid. Electronics. 2020; 9 (2):376.
Chicago/Turabian StyleYao Zhang; Fan Zhang; Yu Quan; Pengfei Zhang. 2020. "Analysis of Three-Phase Inverter Parallel Operation with Network-Based Control Having Strong Robustness and Wide Time-Scale Compatibility in Droop-Controlled AC Microgrid." Electronics 9, no. 2: 376.
A redundant unit has been utilized in prior work for a T-type three-level inverter to handle multiple open-circuit faults, but the output was limited to two levels. In this paper, equivalent switching state and improved virtual vector methods are proposed to complement switching states and provide better fault-tolerant performance. Under fault scenarios, equivalent replacement of unreachable switching states can be used to generate the target line-to-line voltages. If the replacement cannot be achieved by equivalent switching states, a virtual vector with redundant capability is employed to support two and three-level modulation at the output. The rearranged switching sequences can be formed by employing virtual vectors and existing vectors. In addition, by reconstructing the virtual vectors, a balancing method is adopted to eliminate neutral point voltage offset in cases of multiple faults. Experimental tests verify the effectiveness and feasibility of the proposed method.
Borong Wang; Zhan Li; Minghan Dong; Zhihong Bai; Philip T. Krein; Hao Ma. Recovering Partial Three-Level Operation in a T-Type Inverter With Fault Management Redundant Unit. IEEE Transactions on Power Electronics 2020, 35, 8944 -8955.
AMA StyleBorong Wang, Zhan Li, Minghan Dong, Zhihong Bai, Philip T. Krein, Hao Ma. Recovering Partial Three-Level Operation in a T-Type Inverter With Fault Management Redundant Unit. IEEE Transactions on Power Electronics. 2020; 35 (9):8944-8955.
Chicago/Turabian StyleBorong Wang; Zhan Li; Minghan Dong; Zhihong Bai; Philip T. Krein; Hao Ma. 2020. "Recovering Partial Three-Level Operation in a T-Type Inverter With Fault Management Redundant Unit." IEEE Transactions on Power Electronics 35, no. 9: 8944-8955.
Zhan Li; Pat Wheeler; Alan Watson; Alessandro Costabeber; Borong Wang; Yini Ren; Zhihong Bai; Hao Ma. A Fast Diagnosis Method for Both IGBT Faults and Current Sensor Faults in Grid-Tied Three-Phase Inverters With Two Current Sensors. IEEE Transactions on Power Electronics 2019, 35, 5267 -5278.
AMA StyleZhan Li, Pat Wheeler, Alan Watson, Alessandro Costabeber, Borong Wang, Yini Ren, Zhihong Bai, Hao Ma. A Fast Diagnosis Method for Both IGBT Faults and Current Sensor Faults in Grid-Tied Three-Phase Inverters With Two Current Sensors. IEEE Transactions on Power Electronics. 2019; 35 (5):5267-5278.
Chicago/Turabian StyleZhan Li; Pat Wheeler; Alan Watson; Alessandro Costabeber; Borong Wang; Yini Ren; Zhihong Bai; Hao Ma. 2019. "A Fast Diagnosis Method for Both IGBT Faults and Current Sensor Faults in Grid-Tied Three-Phase Inverters With Two Current Sensors." IEEE Transactions on Power Electronics 35, no. 5: 5267-5278.
Medium voltage high-speed drive is promising in applications such as the centrifugal compressors and electrified transportation. However, it raises lots of design challenges for the converters which drive the motors. A SiC & Si Hybrid ANPC converter is developed to address those challenges. In this paper, the essence of this hybrid structure is investigated to clearly show the derivation process of the hybrid active neutral point clamped (ANPC) converter and inspire future research on these hybrid topologies. A dedicated space vector modulation (SVM) scheme is proposed for the hybrid ANPC converter, which enables the three-phase hybrid ANPC converter operating with SiC MOSFETs in high frequency and Si IGBTs in fundamental frequency. A neutral point (NP) voltage balancing scheme is added to the SVM scheme to balance the NP voltage imbalance under low-frequency modulation index. All these efforts make the hybrid ANPC converter become a high power density and fairly low-cost solution. A 400Hz fundamental frequency, 3.6kHz switching frequency, medium voltage high-speed drive system is assumed and tested by the scaled-down experimental results. the effectiveness of the proposed SVM and NP voltage balancing method have both been verified.
Chushan Li; Rui Lu; Chengmin Li; Wuhua Li; Xiaowei Gu; Youtong Fang; Hao Ma; Xiangning He. Space Vector Modulation for SiC and Si Hybrid ANPC Converter in Medium-Voltage High-Speed Drive System. IEEE Transactions on Power Electronics 2019, 35, 3390 -3401.
AMA StyleChushan Li, Rui Lu, Chengmin Li, Wuhua Li, Xiaowei Gu, Youtong Fang, Hao Ma, Xiangning He. Space Vector Modulation for SiC and Si Hybrid ANPC Converter in Medium-Voltage High-Speed Drive System. IEEE Transactions on Power Electronics. 2019; 35 (4):3390-3401.
Chicago/Turabian StyleChushan Li; Rui Lu; Chengmin Li; Wuhua Li; Xiaowei Gu; Youtong Fang; Hao Ma; Xiangning He. 2019. "Space Vector Modulation for SiC and Si Hybrid ANPC Converter in Medium-Voltage High-Speed Drive System." IEEE Transactions on Power Electronics 35, no. 4: 3390-3401.
T-type multilevel $\rm (T^{2}ML)$ inverters feature low total harmonic distortion and high efficiency. Reliability improvement is particularly important for $\rm T^{2}ML$ inverters because they have high power device count. Methods that provide $\rm T^{2}ML$ inverters with the ability to tolerate simultaneous failures of multiple switches in several legs have not been addressed in the existing literature. This paper proposes a redundant unit that can be shared across phases in a T-type three-level inverter topology to manage open-circuit faults in multiple legs. The redundant unit includes two switches and six diodes, with the extra active switches connected by diodes to each middle switch of the base inverter. Under fault conditions, a standby parallel leg consisting of middle switches and the added redundant devices can be formed in each phase of the inverter to provide an extra current path connecting the DC bus and loads. The middle switches can share the redundant unit simultaneously to replace faulted halfbridge switches. By these means, open-circuit faults in multiple legs can be tolerated simultaneously and the rated output capacity can be maintained during faulted operation. Experimental tests are given to verify the effectiveness and feasibility of this proposed fault-tolerant method.
Borong Wang; Zhan Li; Zhihong Bai; Philip T. Krein; Hao Ma. A Redundant Unit to Form T-Type Three-Level Inverters Tolerant of IGBT Open-Circuit Faults in Multiple Legs. IEEE Transactions on Power Electronics 2019, 35, 924 -939.
AMA StyleBorong Wang, Zhan Li, Zhihong Bai, Philip T. Krein, Hao Ma. A Redundant Unit to Form T-Type Three-Level Inverters Tolerant of IGBT Open-Circuit Faults in Multiple Legs. IEEE Transactions on Power Electronics. 2019; 35 (1):924-939.
Chicago/Turabian StyleBorong Wang; Zhan Li; Zhihong Bai; Philip T. Krein; Hao Ma. 2019. "A Redundant Unit to Form T-Type Three-Level Inverters Tolerant of IGBT Open-Circuit Faults in Multiple Legs." IEEE Transactions on Power Electronics 35, no. 1: 924-939.
Potential performance improvements can be obtained by introducing communication techniques in the power electronic systems. However, network-induced time-delay could bring negative consequences of degrading performance or destabilizing the system in many cases. To investigate and handle the impacts of time-delay, a suit of analytical methodology is proposed, where both delay-insensitive and delay-sensitive control strategies of network-based system have their theoretical methods and different problem-solving paths. The former is to predict the maximum allowable boundaries of time-delay for releasing more network resources, and the latter is to use the controller-altering method for changing its original instability, respectively. The proposed methodology is concretely applied in network-based system of droop-controlled AC (Alternating Current) microgrid in islanded mode. Two different current-sharing strategies are mathematically analyzed and given to verify their validity. Experimental results also show the effectiveness of the proposed methodology in droop-controlled AC microgrid system, which provides theoretical guidance on how to use network-based control for the other power electronic systems.
Yao Zhang. Analysis Methodology for Evaluation of Time-Delay Impact on Network-Based System for Droop-Controlled AC Microgrid. Electronics 2019, 8, 380 .
AMA StyleYao Zhang. Analysis Methodology for Evaluation of Time-Delay Impact on Network-Based System for Droop-Controlled AC Microgrid. Electronics. 2019; 8 (4):380.
Chicago/Turabian StyleYao Zhang. 2019. "Analysis Methodology for Evaluation of Time-Delay Impact on Network-Based System for Droop-Controlled AC Microgrid." Electronics 8, no. 4: 380.
In general, the integral sliding mode control (ISMC) with an integral sliding surface would lead to tracking errors under unbalanced and harmonic grid voltage conditions. In order to eliminate tracking errors under these conditions, multi-resonant items are added to the conventional integral sliding surface in the proposed strategy, which can be called multi-resonant-based sliding mode control (MRSMC). A comparison of tracking precision on the ISMC and MRSMC is analyzed. In order to regulate the system powers directly, the errors of instantaneous active and reactive powers are selected as the state variables. Finally, the output current harmonics and a majority of the doubly-fed induction generator’s (DFIG) electromagnetic torque pulsations can be removed under unbalanced and harmonic grid voltage conditions. Simulation and experimental results are presented to verify the correctness and effectiveness of the proposed strategy.
Yu Quan; Lijun Hang; Yuanbin He; Yao Zhang. Multi-Resonant-Based Sliding Mode Control of DFIG-Based Wind System under Unbalanced and Harmonic Network Conditions. Applied Sciences 2019, 9, 1124 .
AMA StyleYu Quan, Lijun Hang, Yuanbin He, Yao Zhang. Multi-Resonant-Based Sliding Mode Control of DFIG-Based Wind System under Unbalanced and Harmonic Network Conditions. Applied Sciences. 2019; 9 (6):1124.
Chicago/Turabian StyleYu Quan; Lijun Hang; Yuanbin He; Yao Zhang. 2019. "Multi-Resonant-Based Sliding Mode Control of DFIG-Based Wind System under Unbalanced and Harmonic Network Conditions." Applied Sciences 9, no. 6: 1124.