|
|
|
| Delta-Sigma Modulation of Two Stage Matrix Converter with Reference Voltage Correction |
| Zhou Zhanqing1, Xie Qikun1, Ma Chaolei2, Xue Lingyue1, Shi Tingna3 |
1. National Joint Local Engineering Research Center of Electrical Machine System Intelligent Design and Manufacturing Tiangong University Tianjin 300387 China;
2. School of Electrical and Information Engineering Tianjin University Tianjin 300072 China;
3. College of Electrical Engineering Zhejiang University Hangzhou 310027 China |
|
|
|
Abstract A two-stage matrix converter (TSMC) has the advantages of a conventional matrix converter, such as no DC-bus capacitance, flexible energy control, and a compact structure. Moreover, it simplifies the modulation process while avoiding the complex four-step commutation mechanism of direct matrix converters, becoming a potential power electronics topology. Currently, the voltage transfer ratio of TSMC using the classical method cannot exceed 0.866, and the electromagnetic noise caused by voltage harmonic near the switching frequency is relatively concentrated. According to the specific mathematical laws, the spread spectrum modulation technology transforms PWM waveforms into irregular pulse sequences. It improves the voltage transfer ratio and expands the output voltage spectrum to a wider range, thereby reducing output harmonics and electromagnetic noise. However, TSMC has a large number of power switches, and its switching coordination between the rectifier and inverter stage is complex. There are still many key issues to be addressed in the spread spectrum modulation technology of TSMC.
Considering the simple structure and without complex random statistical characteristics, Delta-Sigma modulation (DSM) can significantly optimize the output spectrum, reduce the EMI level, and optimize the operational efficiency of the power converter. However, the modulation strategy of TSMC can be divided into rectifier-stage algorithms and inverter-stage algorithms. The absence of a DC-link capacitor of TSMC leads to fluctuations in DC-link voltage. The DSM of the inverter stage cannot accurately quantify and track the fluctuation patterns of DC-link voltage, making it difficult for TSMC to directly implement DSM in the inverter stage.
This paper proposes a DSM scheme with reference voltage correction (RVC-DSM). Firstly, the operation principle of DSM indicates that as the order L of DSM increases, the suppression effect on low-frequency harmonics of voltage is better, and the modulator resolution is significantly improved. Specifically, the DSM resolution is increased by L+0.5 bits when its operating frequency is doubled. Then, to ensure the voltage utilization of TSMC, the rectifier stage still adopts SVM without zero-vector, and DSM is only employed on the inverter stage to achieve spread spectrum modulation. Meanwhile, limiting the switching frequency for switching loss reduction and solving the problem of voltage tracking are necessary. This paper utilizes the “Voronoi quantizer”, shaped like a Voronoi diagram as the vector partitioning rule, to implement the DSM strategy of TSMC. Finally, combined with the modulation target, the compensation coefficients of the DSM under different DC-link voltages are obtained by analyzing the DC-link voltage fluctuation in different sectors. Furthermore, the compensation coefficients are allocated to the reference voltage in real-time to eliminate the impact of DC-link voltage fluctuations on DSM, achieving efficient spread spectrum modulation of TSMC.
Experiments were carried out on the platform with a dual-core controller of “FPGA+DSP” to verify the proposed RVC-DSM. The experimental results show that the harmonics originally related to the switching frequency (5 kHz, 10 kHz, …) under SVM modulation have been suppressed, and this part of harmonic energy has been extrapolated to the high-frequency band. The low-pass characteristics of the inductance load effectively reduce the conducted interference of TSMC in the 0~30 MHz band. At the same time, RVC-DSM directly employs the basic voltage vector of the inverter stage, ensuring good operating performance in the over- modulation region. Finally, benefiting from its spectrum-shaping effect, the operational efficiency of the RVC-DSM strategy is much higher than that of the SVM strategy.
The following conclusions can be drawn through theoretical analysis and experimental verification. (1) By utilizing the spectrum shaping ability of the RVC-DSM modulator, the high-frequency harmonics near switching frequencies and its octave components are significantly reduced. (2) RVC-DSM can directly use the basic vector of the inverter stage. Its theoretical limit voltage transmission ratio fluctuates between 1.0 and 1.155, improving the TSMC voltage transmission ratio. (3) The switching frequency of RVC-DSM is directly related to its control period. By adopting a shorter control period, the tracking performance of the algorithm is better, and EMI can be improved significantly.
|
|
Received: 16 March 2023
Published: 07 June 2024
|
|
|
|
|
|
[1] 梅杨, 许策, 鲁乔初. 基于零矢量嵌入的双向隔离型AC-DC矩阵变换器分段同步控制策略[J]. 电工技术学报, 2021, 36(22): 4784-4794.
Mei Yang, Xu Ce, Lu Qiaochu.Piecewise syn- chronous control strategy of bidirectional isolated matrix AC-DC converter based on zero vector embedded[J]. Transactions of China Electrotechnical Society, 2021, 36(22): 4784-4794.
[2] 齐琛, 陈希有. 一种可靠换流的双级矩阵变换器载波调制策略[J]. 电工技术学报, 2013, 28(6): 184-191.
Qi Chen, Chen Xiyou.A carrier-based modulation strategy of two stage matrix converter with reliable commutation[J]. Transactions of China Electrotech- nical Society, 2013, 28(6): 184-191.
[3] 王文圣, 李珊瑚, 刘旭, 等. 一种基于输入电流矢量相位的新型间接矩阵变换器空间矢量过调制策略[J]. 电气技术, 2020, 21(3): 1-10.
Wang Wensheng, Li Shanhu, Liu Xu, et al.A novel space vector overmodulation strategy based on input current vector phase for indirect matrix converter[J]. Electrical Engineering, 2020, 21(3): 1-10.
[4] 肖蕙蕙, 魏苏东, 郭强, 等. 优化开关序列的PWM整流器模型预测控制策略[J]. 电工技术学报, 2022, 37(14): 3665-3675, 3700.
Xiao Huihui, Wei Sudong, Guo Qiang, et al.Model predictive control strategy for PWM rectifier with optimized switching sequence[J]. Transactions of China Electrotechnical Society, 2022, 37(14): 3665-3675, 3700.
[5] 何杰, 刘钰山, 毕大强, 等. 开关变换器传导干扰抑制策略综述[J]. 电工技术学报, 2022, 37(6): 1455-1472.
He Jie, Liu Yushan, Bi Daqiang, et al.Review of conducted electromagnetic interference suppression strategies for switching converters[J]. Transactions of China Electrotechnical Society, 2022, 37(6): 1455-1472.
[6] Chang Qingyun, Zhou Bo, Lu Chengjia, et al.Mains current distortion analysis and suppression method for third-harmonic injection two-stage matrix conver- ter[J]. IEEE Transactions on Industrial Electronics, 2023, 70(3): 2168-2177.
[7] 夏长亮, 阎彦. 矩阵变换器-永磁同步电机系统[J]. 电工技术学报, 2015, 30(23): 1-9.
Xia Changliang, Yan Yan.Matrix converter-permanent magnet synchronous motor drives[J]. Transactions of China Electrotechnical Society, 2015, 30(23): 1-9.
[8] Chen Jianan, Jiang Dong, Sun Wei, et al.A family of spread-spectrum modulation schemes based on dis- tribution characteristics to reduce conducted EMI for power electronics converters[J]. IEEE Transactions on Industry Applications, 2020, 56(5): 5142-5157.
[9] 蒋栋, 沈泽微, 刘自程, 等. 电力推进系统电力电子噪声的主动抑制技术进展[J]. 中国电机工程学报, 2020, 40(16): 5291-5302.
Jiang Dong, Shen Zewei, Liu Zicheng, et al.Progress in active mitigation technologies of power electronics noise for electrical propulsion system[J]. Proceedings of the CSEE, 2020, 40(16): 5291-5302.
[10] 邱子桢, 陈勇, 成海全, 等. 基于周期谐波扩频调制的永磁同步电机高频边带声振抑制[J]. 电工技术学报, 2022, 37(10): 2459-2468.
Qiu Zizhen, Chen Yong, Cheng Haiquan, et al.Periodic harmonic spread spectrum modulation for high-frequency sideband vibro-acoustic suppression in permanent magnet synchronous motor[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(10): 2459-2468.
[11] Jacob B, Baiju M R.Spread spectrum modulation scheme for two-level inverter using vector quantised space vector-based pulse density modulation[J]. IET Electric Power Applications, 2011, 5(7): 589.
[12] Xu Jie, Nie Ziling, Zhu Junjie.Characterization and selection of probability statistical parameters in random slope PWM based on uniform distribution[J]. IEEE Transactions on Power Electronics, 2021, 36(1): 1184-1192.
[13] Mathe L, Lungeanu F, Sera D, et al.Spread spectrum modulation by using asymmetric-carrier random PWM[J]. IEEE Transactions on Industrial Electronics, 2012, 59(10): 3710-3718.
[14] Colodro F, Torralba A, Laguna M.Continuous-time Sigma-Delta modulator with an embedded pulsewidth modulation[J]. IEEE Transactions on Circuits and Systems I: Regular Papers, 2008, 55(3): 775-785.
[15] Dunlap S K, Fiez T S.A noise-shaped switching power supply using a Delta-Sigma modulator[J]. IEEE Transactions on Circuits and Systems I: Regular Papers, 2004, 51(6): 1051-1061.
[16] Hwang Y S, Chen J J, Yang J, et al.A low-EMI continuous-time Delta-Sigma-modulator Buck converter with transient response eruption techniques[J]. IEEE Transactions on Industrial Electronics, 2020, 67(8): 6854-6863.
[17] Lumbreras D, Zaragoza J, Berbel N, et al.Com- prehensive analysis of hexagonal Sigma-Delta modulations for three-phase high-frequency VSC based on wide-bandgap semiconductors[J]. IEEE Transactions on Power Electronics, 2021, 36(6): 7212-7222.
[18] Mir T N, Singh B, Bhat A H.Delta-Sigma modulation based common-mode voltage elimination in direct matrix converter[J]. IEEE Transactions on Industrial Informatics, 2021, 17(2): 1048-1057.
[19] 耿乙文, 王亮, 许家斌, 等. 基于Sigma-Delta调制的双两电平逆变器调制策略[J]. 电工技术学报, 2017, 32(18): 239-247.
Geng Yiwen, Wang Liang, Xu Jiabin, et al.A modulation strategy of dual inverter using Sigma-Delta converter[J]. Transactions of China Electrotechnical Society, 2017, 32(18): 239-247.
[20] Hirota A, Nakaoka M.A low noise three-phase matrix converter introducing Delta-Sigma modulation scheme[C]//2006 37th IEEE Power Electronics Specialists Conference, Jeju, Korea (South), 2017: 1-6.
[21] Mir T N, Singh B, Bhat A H.Predictive Delta-Sigma modulation for three-phase to three-phase matrix converters[J]. IEEE Transactions on Power Elec- tronics, 2020, 35(1): 968-976.
[22] Xia Changliang, Li Shanhu, Yan Yan, et al.Research on linear output voltage transfer ratio for ultrasparse matrix converter[J]. IEEE Transactions on Power Electronics, 2016, 31(3): 1811-1815.
[23] 高文科, 阎彦, 史婷娜. 传统矩阵变换器最小相位误差空间矢量过调制策略[J]. 电工技术学报, 2019, 34(2): 316-325.
Gao Wenke, Yan Yan, Shi Tingna.Minimum phase error space-vector over-modulation strategy of con- ventional matrix converter[J]. Transactions of China Electrotechnical Society, 2019, 34(2): 316-325.
[24] Ma Chaolei, Shi Tingna, Lin Zhichen, et al.A novel wider range modulation for indirect matrix converter utilizing Delta-Sigma and space vector[J]. IEEE Transactions on Power Electronics, 2023, 38(2): 1429-1434. |
|
|
|
2024, Vol. 39 
