Switched reluctance motor power converters are prone to open-circuit faults because it need to withstand large voltages and currents.Due to the small number of traditional asymmetrical half bridge topology switches,it...Switched reluctance motor power converters are prone to open-circuit faults because it need to withstand large voltages and currents.Due to the small number of traditional asymmetrical half bridge topology switches,it is difficult to carry out fault tolerant control when power converters has an open-circuit fault,resulting in larger output torque ripple.This paper presents a five-level power converter based on the traditional asymmetric half-bridge power converter.The five-level topology has more switching states and can work in multi-level mode.Based on the topology,different excitation and demagnetization voltages can be choose at different speeds.A fault-tolerance strategy is developed to decrease the influence of the open-circuit fault.The five-level power converter has four switches per phase,and two of them will be used in one of the operating mode.So the remaining two of the switches can be used for safe backup,enabling fault-tolerant control when an open-circuit occur.Since each phase of the five-level power converter proposed in this paper is independent of each other,a reasonable control strategy can be used to avoid the unbalance of the midpoint potential.Finally,the topology and fault-tolerant strategy proposed in this paper are verified by simulation and experiment.展开更多
An improved discontinuous space vector modulation(IDSVM)approach is proposed through analysis of key factors to impact fault tolerance control performance for the AC/DC converter in an all-DC offshore wind power syste...An improved discontinuous space vector modulation(IDSVM)approach is proposed through analysis of key factors to impact fault tolerance control performance for the AC/DC converter in an all-DC offshore wind power system.The three main factors being studied are compensation ratios of active vectors,type of vectors used to resynthesize reference voltage vector and zero vectors distribution in time domain.Their effects are discussed from perspective of energy input,transmission and loss in the AC/DC converter.Three schemes using different compensation ratios for active vectors are compared,and scheme C using projections on current axis achieves better fault tolerance performance.In this paper,the distorted voltage vector is used to synthesize reference voltage vector and the healthy zero vector is redistributed in the twelve sectors.The former is beneficial to reduce three-phase current spikes and the latter helps to stabilize DC-link voltage.Performances of the improved modulation approach are verified on an experimental platform simulating the offshore wind turbine with single switch and multiple switch open-circuit faults.Its robustness and high performance are thoroughly evaluated.展开更多
In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed i...In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed in this paper, together with its hardware structure and software flow chart. Fault waveform regenerator mainly depends on its power amplifiers (PAs) to regenerate the fault waveforms recorded by digital fault recorder (DFR). To counteract the PA’s inherent nonlinear distortions, a digital closed-loop modification technique that is different from the predistortion technique is conceived. And the experimental results verify the effectiveness of the fault waveform regenerator based on the digital closed-loop modification technique.展开更多
针对馈线自动化的功能测试问题,为避免配电终端接入实际配电网进行测试实验可能对电力系统的安全运行造成不利影响,同时为了提高测试的灵活性、效率性和正确性,文中提出了一种虚实结合的馈线自动化测试方法,利用RTLAB(Real Time Laborat...针对馈线自动化的功能测试问题,为避免配电终端接入实际配电网进行测试实验可能对电力系统的安全运行造成不利影响,同时为了提高测试的灵活性、效率性和正确性,文中提出了一种虚实结合的馈线自动化测试方法,利用RTLAB(Real Time Laboratory)实时全数字仿真器搭建配电网并模拟故障运行,设计具备保护、重合闸、就地式FA(Feeder Automation)功能的仿真型虚拟配电终端用于开展RTLAB实时仿真器与物理模型硬件在环仿真研究。文中设计的基于高性能线性功率放大器的接口实施方案被测配电终端接入测试系统形成闭环,构建了虚实结合的馈线自动化仿真测试环境。通过开展基本故障处理能力测试和容错能力测试的硬件在环仿真实验,验证了接口装置的准确性,同时验证了测试平台的有效性。展开更多
文摘Switched reluctance motor power converters are prone to open-circuit faults because it need to withstand large voltages and currents.Due to the small number of traditional asymmetrical half bridge topology switches,it is difficult to carry out fault tolerant control when power converters has an open-circuit fault,resulting in larger output torque ripple.This paper presents a five-level power converter based on the traditional asymmetric half-bridge power converter.The five-level topology has more switching states and can work in multi-level mode.Based on the topology,different excitation and demagnetization voltages can be choose at different speeds.A fault-tolerance strategy is developed to decrease the influence of the open-circuit fault.The five-level power converter has four switches per phase,and two of them will be used in one of the operating mode.So the remaining two of the switches can be used for safe backup,enabling fault-tolerant control when an open-circuit occur.Since each phase of the five-level power converter proposed in this paper is independent of each other,a reasonable control strategy can be used to avoid the unbalance of the midpoint potential.Finally,the topology and fault-tolerant strategy proposed in this paper are verified by simulation and experiment.
基金funded by National Key Research&Development Program of China under Grant No.2019YFE0104800,Major Research Plan of the National Natural Science Foundation of China under Grant No.92270101.
文摘An improved discontinuous space vector modulation(IDSVM)approach is proposed through analysis of key factors to impact fault tolerance control performance for the AC/DC converter in an all-DC offshore wind power system.The three main factors being studied are compensation ratios of active vectors,type of vectors used to resynthesize reference voltage vector and zero vectors distribution in time domain.Their effects are discussed from perspective of energy input,transmission and loss in the AC/DC converter.Three schemes using different compensation ratios for active vectors are compared,and scheme C using projections on current axis achieves better fault tolerance performance.In this paper,the distorted voltage vector is used to synthesize reference voltage vector and the healthy zero vector is redistributed in the twelve sectors.The former is beneficial to reduce three-phase current spikes and the latter helps to stabilize DC-link voltage.Performances of the improved modulation approach are verified on an experimental platform simulating the offshore wind turbine with single switch and multiple switch open-circuit faults.Its robustness and high performance are thoroughly evaluated.
文摘In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed in this paper, together with its hardware structure and software flow chart. Fault waveform regenerator mainly depends on its power amplifiers (PAs) to regenerate the fault waveforms recorded by digital fault recorder (DFR). To counteract the PA’s inherent nonlinear distortions, a digital closed-loop modification technique that is different from the predistortion technique is conceived. And the experimental results verify the effectiveness of the fault waveform regenerator based on the digital closed-loop modification technique.
文摘针对馈线自动化的功能测试问题,为避免配电终端接入实际配电网进行测试实验可能对电力系统的安全运行造成不利影响,同时为了提高测试的灵活性、效率性和正确性,文中提出了一种虚实结合的馈线自动化测试方法,利用RTLAB(Real Time Laboratory)实时全数字仿真器搭建配电网并模拟故障运行,设计具备保护、重合闸、就地式FA(Feeder Automation)功能的仿真型虚拟配电终端用于开展RTLAB实时仿真器与物理模型硬件在环仿真研究。文中设计的基于高性能线性功率放大器的接口实施方案被测配电终端接入测试系统形成闭环,构建了虚实结合的馈线自动化仿真测试环境。通过开展基本故障处理能力测试和容错能力测试的硬件在环仿真实验,验证了接口装置的准确性,同时验证了测试平台的有效性。
