1. School of Electrical and Information Engineering Zhengzhou University of light industry Zhengzhou 450002 China;
2. RVC-National Engineering Lab Hunan University Changsha 410082 China;
3. College of Electrical and Information Engineering Hunan Institute of Engineering Xiangtan 411104 China
With the development of power electronics and control theory, AC drive systems are widely used in industrial production, transportation, military aerospace, and other fields. In the AC servo control system, the motor phase current is the core parameter to the vector control, and the detection and feedback of the phase current are of great significance in improving the control system's performance. The traditional vector control system needs at least two current sensors installed on the AC output side through the space voltage pulse width modulation (SVPWM) method to achieve phase current acquisition and real-time feedback. Multiple sensors will inevitably increase the system cost and equipment volume, which is not conducive to the development of control equipment miniaturization. Furthermore, the inconsistencies between multiple sensors will deteriorate the performance of the system. To improve these problems, based on the DC bus single sensor sampling principle and traditional SVPWM method, this paper proposes a complementary non-zero vector pulse width modulation (CNSVPWM) method. CNSVPWM utilizes the DC bus single sensor to carry out the phase current time-sharing acquisition under the action of the complementary non-zero vectors and complete the reconstruction of three-phase currents. Thus, accurate feedback on current information is achieved while reducing the cost and volume of the control system.
Firstly, according to the switching states of the three-phase two-level inverter, six effective voltage vectors and two zero vectors are defined, and the corresponding relationship between the DC bus current idc and the phase current can be obtained. Then, the characteristics of the switching devices and the establishment process of the DC bus current are analyzed. The shortest time for the DC bus current to reach a steady state is obtained. That is, the minimum sampling time Tmin for current sampling. According to the minimum sampling time, each sector is divided into the observable area, sector boundary, and low modulation area. The effective voltage vector not meeting the minimum sampling time requirement is defined as a current reconstruction blind area, where the current cannot be completely reconstructed. Aiming at the current reconstruction blind area and based on the volt-second balance principle, the CNSVPWM method utilizes a pair of complementary non-zero vectors to extend the voltage vector action time. For the CNSVPWM method, the duty cycle of effective vectors in each carrier period TS does not change, and the symmetry of the PWM is retained.
In the open-loop experiments, the PWM carrier frequency is set to 10 kHz, the sampling frequency is 20 kHz, and the modulation index is M=0.55. MDA805A motor drive analyzer is used to collect and analyze the experimental data. In sector switching, the CNSVPWM waveform is normally sent, and two sample pulses can be accurately triggered. When the reference voltage vector enters the sector boundary area, the three-phase current can be completely reconstructed, and the reconstruction error is 2.72 %. To further verify the effectiveness of the proposed method, the experiments are carried out under two dynamic conditions of motor acceleration and deceleration. When the rotational speed changes, the reconstructed phase current can follow the measured phase current in real-time. The FFT results show that compared with the SVPWM method, the current harmonic THD of CNSVPWM is increased by 2.04 %, from 4.11 % to 6.15 %.
The following conclusions are drawn through experiments: (1) The CNSVPWM method retains the symmetry of the PWM waveform and does not affect the duty cycle. (2) The CNSVPWM extends the current sampling window and realizes the phase current reconstruction in the middle modulation area. (3) The current THD of CNSVPWM is less than 6.15 %, reconstruction error is less than 3 %.
[1] Xu Yongxiang, Yuan Qingbing, Zou Jinbin, et al.Sinusoidal periodic carrier frequency modulation in reducing electromagnetic noise of permanent magnet synchronous motor[J]. IET Electric Power Appli- cations, 2013, 7(3): 223-230.
[2] Cheng Xiaomeng, Lu Haifeng, Qu Wenlong, et al.Single current sensor operation with fixed sampling points using a common-mode voltage reduction PWM technique[C]//2009IEEE6th International Power Elec- tronics and Motion Control Conference, Wuhan, China, 2009: 479-483.
[3] 魏海峰, 陆彦如, 江廷宇, 等. 考虑非观测区补偿的永磁同步电机单电阻采样重构[J]. 电工技术学报, 2018, 33(12): 2695-2702.
Wei Haifeng, Lu Yanru, Jiang Tingyu, et al.Single resistor sampling reconstruction of permanent magnet synchronous motor considering non-observation area compensation[J]. Transactions of China Electrotech- nical Society, 2018, 33(12): 2695-2702.
[4] Sun Kai, Wei Qing, Huang Lipei, et al.An over- modulation method for PWM-inverter-fed IPMSM drive with single current sensor[J]. IEEE Transactions on Industrial Electronics, 2010, 57(10): 3395-3404.
[5] 周聪, 刘闯, 王凯, 等. 用于开关磁阻电机驱动系统的新型单电阻电流采样技术[J]. 电工技术学报, 2017, 32(5): 55-61.
Zhou Cong, Liu Chuang, Wang Kai, et al A novel single resistance current sampling technique of switched reluctance motor[J]. Transactions of China Electrotechnical Society, 2017, 32(5): 55-61.
[6] 翁汉琍, 贾永波, 李振兴, 等. 二维空间重构电流特征轨迹的变压器差动保护判据[J]. 电力系统自动化, 2020, 44(9): 144-150.
Weng Hanli, Jia Yongbo, Li Zhenxing, et al.Transformer differential protection criterion based on reconstructed trajectory of current characteristics in two-dimensional space[J]. Automation of Electric Power Systems, 2020, 44(9): 144-150.
[7] 赵仕策, 赵洪山, 寿佩瑶. 智能电力设备关键技术及运维探讨[J]. 电力系统自动化, 2020, 44(20): 1-10.
Zhao Shice, Zhao Hongshan, Shou Peiyao.Discussion on key technology and operation & maintenance of intelligent power equipment[J]. Automation of Elec- tric Power Systems, 2020, 44(20): 1-10.
[8] 黄科元, 伍瑞泽, 黄守道, 等. 单电阻采样的永磁同步电动机相电流重构策略[J]. 电力系统及其自动化学报, 2018, 30(9): 114-120.
Huang Keyuan, Wu Ruize, Huang Shoudao, et al.Phase current reconstruction strategy for PMSM using one-shunt current sampling[J]. Proceedings of the CSU-EPSA, 2018, 30(9): 114-120.
[9] 陆佳琪, 吴金富, 陆彦如, 等. 永磁同步电机新型单电阻电流重构技术研究[J]. 电机与控制应用, 2019, 46(2): 46-51.
Lu Jiaqi, Wu Jinfu, Lu Yanru, et al.A novel single- resistance current reconfiguration technique for per- manent magnet synchronous motor[J]. Electric Machines & Control Application, 2019, 46(2): 46-51.
[10] 马鸿雁, 孙凯, 魏庆, 等. PWM逆变器相电流重构研究与误差分析[J]. 电工技术学报, 2011, 26(1): 108-114, 161.
Ma Hongyan, Sun Kai, Wei Qing, et al.Phase current reconstruction method for PWM inverter and error analysis[J]. Transactions of China Electrotechnical Society, 2011, 26(1): 108-114, 161.
[11] Lee W C, Hyun D S, Lee T K.A novel control method for three-phase PWM rectifiers using a single current sensor[J]. IEEE Transactions on Power Electronics, 2000, 15(5): 861-870.
[12] Lai Y S, Lin Yongkai, Chen C W.New hybrid pulse width modulation technique to reduce current dis- tortion and extend current reconstruction range for a three-phase inverter using only DC-link sensor[J]. IEEE Transactions on Power Electronics, 2013, 28(3): 1331-1337.
[13] 王文杰, 闫浩, 邹继斌, 等. 基于混合脉宽调制技术的永磁同步电机过调制区域相电流重构策略[J]. 中国电机工程学报, 2021, 41(17): 6050-6060.
Wang Wenjie, Yan Hao, Zou Jibin, et al.Phase current reconstruction strategy of PMSM under over- modulation mode based on a hybrid space vector pulse width modulation technique[J]. Proceedings of the CSEE, 2021, 41(17): 6050-6060.
[14] Lu Haifeng, Cheng Xiaomeng, Qu Wenlong, et al.A three-phase current reconstruction technique using single DC current sensor based on TSPWM[J]. IEEE Transactions on Power Electronics, 2014, 29(3): 1542-1550.
[15] 闫朝阳, 张喆, 李建霞, 等. 单相高频链逆变器的解结耦单极性移相调制及其死区优化[J]. 电工技术学报, 2018, 33(6): 1337-1346.
Yan Zhaoyang, Zhang Zhe, Li Jianxia, et al.The uni-polarity phase-shifted modulation strategy for single-phase high-frequency link inverter based on de-re-coupling idea and dead time optimization[J]. Transactions of China Electrotechnical Society, 2018, 33(6): 1337-1346.
[16] 申永鹏, 王前程, 王延峰, 等. 误差自校正混合脉宽调制策略[J]. 电工技术学报, 2022, 37(14): 3643-3653.
Shen Yongpeng, Wang Qiancheng, Wang Yanfeng, et al.Error self-correction mixed pulse width modu- lation strategy[J]. Transactions of China Electro- technical Society, 2022, 37(14): 3643-3653.
[17] 申永鹏, 王帅兵, 梁伟华, 等. T型三电平逆变器合成脉冲宽度调制相电流重构策略[J]. 电工技术学报, 2022, 37(20): 5302-5312.
Shen Yongpeng, Wang Shuaibing, Liang Weihua, et al.T-type three-level inverter composite pulse width modulation phase current reconstruction strategy[J]. Transactions of China Electrotechnical Society, 2022, 37(20): 5302-5312.
[18] 肖飞, 许观达, 连传强, 等. 永磁同步电机单电流传感器系统的三相电流重构策略[J]. 电工技术学报, 2022, 37(7): 1609-1617.
Xiao Fei, Xu Guanda, Lian Chuanqiang, et al.Three- phase current reconstruction strategy of permanent magnet synchronous machine drives using a single current sensor[J]. Transactions of China Electro- technical Society, 2022, 37(7): 1609-1617.
[19] 黄梓欣, 林湘宁, 马啸, 等. 含风电继电保护应用中的电流互感器饱和电流重构方法[J]. 电工技术学报, 2022, 37(19): 4823-4834.
Huang Zixin, Lin Xiangning, Ma Xiao, et al.Recon- struction method of saturation current of current transformer in relay protection application related to wind power[J]. Transactions of China Electrote- chnical Society, 2022, 37(19): 4823-4834.
[20] 谷明月, 何媛媛. 基于半PWM移相的单电阻电流重构策略研究[J]. 微电机, 2019, 52(6): 62-66.
Gu Mingyue, He Yuanyuan.Research on single-shunt current sensing method based on half PWM phase shift[J]. Micromotors, 2019, 52(6): 62-66.
[21] Ha J I.Current prediction in vector-controlled PWM inverters using single DC-link current sensor[J]. IEEE Transactions on Industrial Electronics, 2010, 57(2): 716-726.
[22] Gu Yikun, Ni Fenglei, Yang Dapeng, et al.Switching- state phase shift method for three-phase-current reconstruction with a single DC-link current sensor[J]. IEEE Transactions on Industrial Electronics, 2011, 58(11): 5186-5194.
[23] Lu Jiadong, Zhang Xiaokang, Hu Yihua, et al.Independent phase current reconstruction strategy for IPMSM sensorless control without using null switching states[J]. IEEE Transactions on Industrial Electronics, 2018, 65(6): 4492-4502.
[24] 申永鹏, 郑竹风, 杨小亮, 等. 直流母线电流采样电压空间矢量脉冲宽度调制[J]. 电工技术学报, 2021, 36(8): 1617-1627.
Shen Yongpeng, Zheng Zhufeng, Yang Xiaoliang, et al.A compatible SVPWM method for DC bus current sampling[J]. Transactions of China Electrotechnical Society, 2021, 36(8): 1617-1627.
[25] Im J H, Kim R Y.Improved saliency-based position sensorless control of interior permanent-magnet syn- chronous machines with single DC-link current sensor using current prediction method[J]. IEEE Transa- ctions on Industrial Electronics, 2018, 65(7): 5335-5343.
[26] 倪瑞政, 李庭, 陈杰, 等. 一种脉冲式死区补偿方法的研究[J]. 电工技术学报, 2019, 34(增刊2): 553-559.
Ni Ruizheng, Li Ting, Chen Jie, et al.Research on a pulse dead zone compensation method[J]. Transa- ctions of China Electrotechnical Society, 2019, 34(S2): 553-559.