Rongfeng Yang
Harbin Institute of Technology
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Featured researches published by Rongfeng Yang.
IEEE Transactions on Industrial Electronics | 2013
Gaolin Wang; Rongfeng Yang; Dianguo Xu
A position sensorless control strategy of an interior permanent magnet synchronous motor (IPMSM) drive based on a digital signal processor (DSP) is proposed. To achieve sensorless wide-speed-range operation, a hybrid position estimation strategy combining the high frequency (HF) signal injection method with the electromotive force (EMF)-based method is presented. At low-speed range, an HF voltage signal is injected, and a rotor position observer is designed to improve the robustness to the load disturbance. At middle- and high-speed ranges, a sliding-mode observer based on the extended EMF of IPMSM is designed for sensorless operation. Moreover, during the switch-over area, the two position estimation methods are both enabled for the sensorless control. A software phase-locked loop and a dead-time compensation strategy are adopted to improve the position estimation accuracy. The experimental results demonstrate the feasibility of the control strategy with a sensorless IPMSM drive based on a DSP.
IEEE Transactions on Power Electronics | 2015
Binbin Li; Rongfeng Yang; Dandan Xu; Gaolin Wang; Wei Wang; Dianguo Xu
The modular multilevel converter (MMC) is an emerging topology for high-power applications and is considered as the development trend of the high-voltage power converters. In this paper, general implementation of the phase-shifted carrier (PSC) modulation with a capacitor voltage balancing method for MMC is first introduced. Then, the mathematical analysis of PSC modulation for MMC is performed to identify the PWM harmonic characteristics of the output voltage and the circulating current. Moreover, influence of the carrier displacement angle between the upper and lower arms on these harmonics is also studied. Using this analysis, the optimum displacement angles are specified for the output voltage harmonics minimization and the circulating current harmonics cancellation, respectively. The harmonic features of the line-to-line voltage and the dc-link current are also investigated. Moreover, an extension of the PSC modulation for MMC with full-bridge submodules is also proposed which can increase the equivalent switching frequency of the output voltage and circulating current by two times compared with the conventional MMC. Finally, the findings are verified experimentally on a prototype of MMC.
IEEE Transactions on Power Electronics | 2015
Rong Xu; Yong Yu; Rongfeng Yang; Gaolin Wang; Dianguo Xu; Binbin Li; Shunke Sui
This paper presents a transformerless static synchronous compensator (STATCOM) system based on multilevel H-bridge converter with star configuration. This proposed control methods devote themselves not only to the current loop control but also to the dc capacitor voltage control. With regards to the current loop control, a nonlinear controller based on the passivity-based control (PBC) theory is used in this cascaded structure STATCOM for the first time. As to the dc capacitor voltage control, overall voltage control is realized by adopting a proportional resonant controller. Clustered balancing control is obtained by using an active disturbances rejection controller. Individual balancing control is achieved by shifting the modulation wave vertically which can be easily implemented in a field-programmable gate array. Two actual H-bridge cascaded STATCOMs rated at 10 kV 2 MVA are constructed and a series of verification tests are executed. The experimental results prove that H-bridge cascaded STATCOM with the proposed control methods has excellent dynamic performance and strong robustness. The dc capacitor voltage can be maintained at the given value effectively.
IEEE Transactions on Industry Applications | 2012
Gaolin Wang; Guoqiang Zhang; Rongfeng Yang; Dianguo Xu
This paper proposes a novel low-cost control strategy of gearless traction permanent-magnet synchronous machines for direct-drive elevator applications. It can improve robustness of the weight-sensorless traction machine system installed with an ordinary incremental encoder. In order to improve the riding comfort for the passengers during brake releases, a novel starting torque compensation strategy without a weight transducer is presented. After analyzing the dynamic characteristics and the friction torque of the elevator traction system, two starting torque compensation methods based on the dichotomy and the staircase method are proposed for the weight-sensorless elevator applications. This way, electromagnetic torque can be generated to balance the load torque, and sliding can be prevented when the elevator brake releases during the starting operation. To achieve the current vector decoupling control for the traction machine installed with an incremental encoder, the initial rotor position estimation at standstill based on a hybrid signal injection method is adopted. First, a high-frequency oscillating sinusoidal voltage signal is injected to obtain the magnetic pole position. Then, two pulse voltage vectors are injected in the positive and negative directions to identify the magnet polarity. The experimental results demonstrate the feasibility of the proposed control strategy with an 11.7-kW traction machine.
IEEE Transactions on Power Electronics | 2015
Binbin Li; Dandan Xu; Yi Zhang; Rongfeng Yang; Gaolin Wang; Wei Wang; Dianguo Xu
This letter respectively presents two closed-loop precharge control methods to fully charge the submodule (SM) capacitors of the modular multilevel converter (MMC) during dc-side and ac-side start-up processes. The proposed methods are aimed at regulating a constant charging current thus reducing the start-up time and eliminating the inrush current. Besides, capacitor voltage balancing control is also embedded into the controller to equally charge the SM capacitors. Due to the flexibility of the closed-loop control, these methods are applicable to any MMC applications regardless of the number of SMs. Finally, effectiveness of the proposed methods is verified experimentally on a three-phase prototype of MMC.
IEEE Transactions on Industrial Electronics | 2016
Binbin Li; Shaoze Zhou; Dandan Xu; Rongfeng Yang; Dianguo Xu; Concettina Buccella; Carlo Cecati
Modular multilevel converters (MMC) represent an interesting and emerging topology in medium-voltage motor drive applications. The main challenge of using such a topology in variable-speed drives is the large voltage ripple of submodule capacitors at low speed with constant torque. In this paper, an improved circulating current injection method is proposed, which does not completely eliminate the capacitor voltage ripple, but maintains it bounded within reasonable values. As a result, magnitude of injected circulating current is reduced, leading to converter efficiency improvement and reduction of semiconductor current ratings. Dimensioning of submodule capacitance is also discussed, which is an important consideration when designing the MMCs in variable-speed drives. The proposed method has been successfully validated by simulation and experimental results.
IEEE Transactions on Power Electronics | 2015
Binbin Li; Yi Zhang; Rongfeng Yang; Rong Xu; Dianguo Xu; Wei Wang
Redundant submodules (SMs) are always required to ensure the reliability of the modular multilevel converter (MMC). In this letter, a new control method for MMC is proposed to seamlessly ride through the period when bypassing a faulty SM and inserting a redundant SM. With the proposed method, the redundant SMs can be arranged in cold reserve mode so as to reduce the conduction losses, and when faced with SM failures, bypass of the faulty SM and insertion of the redundant SM will incur no inrush current problems. Besides, the capacitor of the newly inserted SM can get linearly charged. Validity of the proposed control method is verified experimentally based on a single-phase MMC prototype.
international conference on power electronics and drive systems | 2009
Wei Chen; Dianguo Xu; Rongfeng Yang; Yong Yu; Zhuang Xu
A novel stator voltage oriented V/F control method for induction motor is presented in this paper to improve the low speed performance and stability of open-loop system. The control scheme adopts a novel stator resistor voltage drop compensation method to ensure the rated stator flux constant over a wide range of operating speeds. And through deeply research of the instability under light load condition, a stabilizing control method is proposed. Under very low speed condition, the performance has greatly improved by boosting the torque and compensating the motor slip frequency. Different from vector control methods, all the compensation and regulation are based on stator voltage oriented synchronous rotation frame transformation, which avoid complicated vector calculation and are simple to implement. The experimental results showed that, by adopting the proposed method, the speed can be accurately controlled down to 0.1 Hz with rated load torque.
the international power electronics conference - ecce asia | 2010
Gaolin Wang; Rongfeng Yang; Yangwei Wang; Yong Yu; Dianguo Xu
An improved initial rotor position estimation method based on signal injection for position sensorless interior permanent magnet synchronous motor (PMSM) at standstill is presented. In first step, high-frequency rotating voltage signal is injected into stator wingding to obtain magnetic pole position. A PI tracing observer is used to regulate the error signal containing magnetic pole position information. When the error signal is regulated to zero, magnetic pole position can be estimated. In second step, in order to identify magnet polarity more easily, two pulse voltage vectors are injected based on the obtained position information in first step. By comparing d-axis stator current values, magnet polarity can be identified. Then the position estimated in the first step can be compensated according to the magnet polarity information. The validity of the proposed estimation scheme is verified by a 22kW interior PMSM. Experimental results show that the method can achieve acceptable estimation accuracy.
conference on industrial electronics and applications | 2010
Rongfeng Yang; Gaoling Wang; Yong Yu; Dianguo Xu; Zhuang Xu
Multilevel voltage technology is widely used in power electric engineering, and the associated modulation method, especially the space vector pulse width modulation (SVPWM) method is researched widely. However, the SVPWM process always becomes complicated when the voltage level increases. Thus this paper presented one generalized fast multilevel SVPWM method, which is based on phase voltage construction so has clear physical concept. The method includes base switch vector selection, dwell time calculation, the switch sequence generation considering redundant states. The method is simple to implement as less calculation, lower memory space, without any lookup table, and the complexity has no relationship with the voltage level exhibiting excellent universality. The simulation results demonstrate the validity of this algorithm.