Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM...Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM)strategy to suppress the ZSC.Five vectors are selected as basic voltage vectors in one switching period.The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector.To suppress the ZSC,a non-zero zero-sequence voltage(ZSV)is generated to compensate the third harmonic back-EMF.Rather than triangular carrier modulation,the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals.The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane.With the proposed method,the ZSC can be considerably reduced.The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy.展开更多
The development of renewable energy power generation for carbon neutrality and energy transition has been increasing worldwide,leading to an increasing demand for high-power conversion.Compared with traditional interl...The development of renewable energy power generation for carbon neutrality and energy transition has been increasing worldwide,leading to an increasing demand for high-power conversion.Compared with traditional interleaved paralleling,the integrated paralleling of three-level inverters can further reduce the output harmonics.Moreover,a well-designed switching sequence ensures that the average circulating current is zero,which provides a superior and feasible solution to satisfy the demands of high-power operations.However,a large instantaneous loop current exists between shunt converters,which leads to disadvantages such as higher switching device stress and loss.In this study,by utilizing the state-distribution redundancy provided by the integrated modulation process,a new design for switch-ing sequences is suggested for the integrated modulation of shunt three-level converters.This design aims to reduce the circulating current while better preserving the same output current harmonics than traditional parallel methods.The proposal includes an in-depth analysis and explanation of the implementation process.Finally,the proposed method is validated through simulations and prototype experi-ments.The results indicate that compared with traditional methods,the adoption of the improved switching sequence presented in this study leads to an average reduction of 3.2%in the total harmonic distortion of the inverter’s output and an average decrease of 32%in the amplitude of the circulating current.Both the output harmonics and circulating currents are significantly suppressed across various modulation indices.展开更多
In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperatur...In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.展开更多
针对三电平中点钳位型NPC(neutral point clamped)变换器开关频率提高导致变换器电流纹波与电磁干扰噪声增大的问题,提出1种基于电流纹波预测的变开关频率调制策略,以降低三电平NPC变换器电流纹波、谐波噪声及电磁干扰噪声。根据电流纹...针对三电平中点钳位型NPC(neutral point clamped)变换器开关频率提高导致变换器电流纹波与电磁干扰噪声增大的问题,提出1种基于电流纹波预测的变开关频率调制策略,以降低三电平NPC变换器电流纹波、谐波噪声及电磁干扰噪声。根据电流纹波的要求计算出开关周期与采样周期并合成最新的开关周期,形成反馈,从而实现变频调制。使随机周期分布在期望周期的周围,从而使变换器的谐波噪声和电磁噪声更加均匀地分布在较宽的频段上,以达到减少变换器电磁噪声的目的,并改善输出电感上的电流纹波。相关仿真及实验结果表明,相较于传统的调制策略,所提调制策略共模噪声降低了约20 dB/μV,差模噪声降低了约10 dB/μV,其输出电感电流纹波幅值也有相应的减少。展开更多
The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active swit...The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active switches compared to the three-level ANPC inverter.The model predictive current control(MPCC)is a promising control method for multi-level inverters.However,the conven-tional MPCC suffers from high computational complexity and tedious weighting factor tuning in multi-level inverter applications.A low-complexity MPCC without weighting factors for a four-level ANPC inverter is proposed in this paper.The computational burden and voltage vector candidate set are reduced according to the relationship between voltage vector and neutral point voltage balance.The proposed MPCC shows excellent steady-state and dynamics performances while ensuring the neutral point voltage balancing.The efficacy of the proposed MPCC is verified by simulation and experimental results.展开更多
中点箝位型(neutral point clamped,NPC)三电平逆变器已被广泛应用,中点电位的平衡是其关键技术之一。首先建立基于零序电压注入的中点电位的数学模型,然后根据模型分析采用三种不同零序电压注入的计算方法。在实验室搭建三电平并网逆...中点箝位型(neutral point clamped,NPC)三电平逆变器已被广泛应用,中点电位的平衡是其关键技术之一。首先建立基于零序电压注入的中点电位的数学模型,然后根据模型分析采用三种不同零序电压注入的计算方法。在实验室搭建三电平并网逆变器实验样机,比较在不同功率因数下,3种不同零序电压注入方法的中点电位动稳态平衡能力。结果表明,3种方法均能很好地平衡中点电位。此外,在实际条件下,上下电容值常会不相等,因此有必要补充在上下电容值误差为12%条件下的实验。实验验证了3种不同零序电压注入方法在上下电容值误差较大时仍能很好地控制中点电位的平衡。展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 51977099。
文摘Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM)strategy to suppress the ZSC.Five vectors are selected as basic voltage vectors in one switching period.The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector.To suppress the ZSC,a non-zero zero-sequence voltage(ZSV)is generated to compensate the third harmonic back-EMF.Rather than triangular carrier modulation,the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals.The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane.With the proposed method,the ZSC can be considerably reduced.The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy.
基金supported by the National Natural Science Foundation of China(Grant No.51977046)Wuxi University Research Start-up Fund for Introduced Talent(2022r021).
文摘The development of renewable energy power generation for carbon neutrality and energy transition has been increasing worldwide,leading to an increasing demand for high-power conversion.Compared with traditional interleaved paralleling,the integrated paralleling of three-level inverters can further reduce the output harmonics.Moreover,a well-designed switching sequence ensures that the average circulating current is zero,which provides a superior and feasible solution to satisfy the demands of high-power operations.However,a large instantaneous loop current exists between shunt converters,which leads to disadvantages such as higher switching device stress and loss.In this study,by utilizing the state-distribution redundancy provided by the integrated modulation process,a new design for switch-ing sequences is suggested for the integrated modulation of shunt three-level converters.This design aims to reduce the circulating current while better preserving the same output current harmonics than traditional parallel methods.The proposal includes an in-depth analysis and explanation of the implementation process.Finally,the proposed method is validated through simulations and prototype experi-ments.The results indicate that compared with traditional methods,the adoption of the improved switching sequence presented in this study leads to an average reduction of 3.2%in the total harmonic distortion of the inverter’s output and an average decrease of 32%in the amplitude of the circulating current.Both the output harmonics and circulating currents are significantly suppressed across various modulation indices.
基金supported by the National Natural Science Foundation of China(No.62271109)。
文摘In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.
文摘针对三电平中点钳位型NPC(neutral point clamped)变换器开关频率提高导致变换器电流纹波与电磁干扰噪声增大的问题,提出1种基于电流纹波预测的变开关频率调制策略,以降低三电平NPC变换器电流纹波、谐波噪声及电磁干扰噪声。根据电流纹波的要求计算出开关周期与采样周期并合成最新的开关周期,形成反馈,从而实现变频调制。使随机周期分布在期望周期的周围,从而使变换器的谐波噪声和电磁噪声更加均匀地分布在较宽的频段上,以达到减少变换器电磁噪声的目的,并改善输出电感上的电流纹波。相关仿真及实验结果表明,相较于传统的调制策略,所提调制策略共模噪声降低了约20 dB/μV,差模噪声降低了约10 dB/μV,其输出电感电流纹波幅值也有相应的减少。
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4201602)the National Natural Science Foundation of China(Grant No.52002409).
文摘The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active switches compared to the three-level ANPC inverter.The model predictive current control(MPCC)is a promising control method for multi-level inverters.However,the conven-tional MPCC suffers from high computational complexity and tedious weighting factor tuning in multi-level inverter applications.A low-complexity MPCC without weighting factors for a four-level ANPC inverter is proposed in this paper.The computational burden and voltage vector candidate set are reduced according to the relationship between voltage vector and neutral point voltage balance.The proposed MPCC shows excellent steady-state and dynamics performances while ensuring the neutral point voltage balancing.The efficacy of the proposed MPCC is verified by simulation and experimental results.
文摘中点箝位型(neutral point clamped,NPC)三电平逆变器已被广泛应用,中点电位的平衡是其关键技术之一。首先建立基于零序电压注入的中点电位的数学模型,然后根据模型分析采用三种不同零序电压注入的计算方法。在实验室搭建三电平并网逆变器实验样机,比较在不同功率因数下,3种不同零序电压注入方法的中点电位动稳态平衡能力。结果表明,3种方法均能很好地平衡中点电位。此外,在实际条件下,上下电容值常会不相等,因此有必要补充在上下电容值误差为12%条件下的实验。实验验证了3种不同零序电压注入方法在上下电容值误差较大时仍能很好地控制中点电位的平衡。
