This paper proposes a new concept of synthesized voltage vector to address dead-time effect issue for Finite Control Set Model Predictive Control(FCS-MPC)technique.For a voltage source inverter(VSI),dead-time is inevi...This paper proposes a new concept of synthesized voltage vector to address dead-time effect issue for Finite Control Set Model Predictive Control(FCS-MPC)technique.For a voltage source inverter(VSI),dead-time is inevitably inserted between the turn off and turn on instants of power devices to avoid short circuit phenomenon.The influence of dead-time leads to output voltage vector error of three-phase inverters.Furthermore,it will result in computing deviation in cost function,and will deteriorate the performance of the system if not properly dealt with.In this paper,the problem is clearly analyzed,and the solution to this issue is proposed by introducing a synthesized voltage vector.The proposed solution is verified by Hardware-in-the-loop(HiL)test in real time,and results validate the effectiveness of the proposed solution.展开更多
The key of speed sensorless vector control system lies in the accurate orientation of magnetic field. In some field-oriented algorithms, the integrator of observers and the dead-time effect bring in system errors duri...The key of speed sensorless vector control system lies in the accurate orientation of magnetic field. In some field-oriented algorithms, the integrator of observers and the dead-time effect bring in system errors during the estimation of field position. In this paper, a saturated feedback integrator is used, and the dead-time effect is compen- sated by current positive feedback. Experiments were carried out on the hardware platform of MCK2407, with chip TMS320LF2407 from TI Company. The results show that the prooosed method is simole and effective, and the accuracy of field position is improved.展开更多
In the inverter circuit,there exists a specific on-off time in each power transistor.As such,to prevent a short circuit of the two switch devices on the upper and lower bridge arms,a specific dead time must be set in ...In the inverter circuit,there exists a specific on-off time in each power transistor.As such,to prevent a short circuit of the two switch devices on the upper and lower bridge arms,a specific dead time must be set in the pulse width modulation(PWM)and the sinusoidal pulse width modulation(SPWM)signals.In this paper,an intellectual property(IP)core that can introduce a high-precision dead time of arbitrary length into PWM or SPWM signals of the inverter is designed to increase the precision,convenience and generalization of dead time control,resulting in a boosted control accuracy of up to 10 ns.Moreover,the added Avalon bus enables IP cores to be accessed by the field programmable gate array(FPGA)processor in a standard manner and multiple IP cores of the same class can be easily incorporated.In addition,an application for setting and compensating for dead time in a three-phase inverter based on system on programmable chip(SOPC)technology is presented.With the Nios II CPU as its core,the system adopts the mean voltage compensation method to calculate the compensation voltage,and performs dead-time compensation in a feed-forward manner.The three dead-time IP cores are controlled by Avalon bus.These allow the dead time of three groups of power transistors to be accurately controlled and flexibly adjusted.The system also features the master computer communication function while boasting the advantages of flexible control,high precision and low cost.展开更多
Subsynchronous resonance(SSR)and high-frequency resonance(HFR)are two phenomena that exist in a doubly fed induction generator(DFIG)system operated in a weak grid.Besides the aforementioned resonance,dead-time in the ...Subsynchronous resonance(SSR)and high-frequency resonance(HFR)are two phenomena that exist in a doubly fed induction generator(DFIG)system operated in a weak grid.Besides the aforementioned resonance,dead-time in the converter(rotor side converter(RSC)and grid side converter(GSC))of the DFIG system can cause resonance at middle frequencies.The aforementioned resonance at middle frequencies can greatly degrade dynamic performance and cause instabilities in the DFIG system.Nevertheless,there is not enough research available in existing literature on resonance in the DFIG system,considering dead-time impact.This paper proposes a new method of resonance analysis in a DFIG system,taking dead-time effect into consideration and utilizing small-signal impedance modeling.Dead-time of the RSC and GSC will introduce distorted voltage into the rotor-and stator-side of the DFIG.Then,rotor-side impedance is modified by adding the effect of transfer function(impedance)from the distorted voltage to rotor current.Likewise,the stator-side impedance is modified by adding the effect of the transfer function(impedance)from distorted voltage to stator current.Thus,overall DFIG system impedance,as seen from the point of common coupling is changed.Finally,resonance is revealed by plotting the DFIG system impedance and weak grid impedance on the Bode plot.Additionally,resonance mitigation is impedance on the Bode plot.Additionally,resonance mitigation is exposed through the dead-time compensation(DTC)technique using an adaptive second-order bandpass filter.With the proposed technique,the resonance at middle frequencies is damped with zero probability of resonance reoccurrence.Finally,the validity and the accuracy of the proposed DTC techniques are validated using mathematical analysis and simulations in Matlab.展开更多
针对电厂中主汽温控制系统具有大滞后、非线性的特点,提出了一种新的基于 Smith 预估器的单神经元 PSD 自适应控制算法,即由 Smith 预估器和单神经元 PSD 自适应控制器组合的复合控制。并且利用Lyapunov 稳定性理论证明了单神经元自适...针对电厂中主汽温控制系统具有大滞后、非线性的特点,提出了一种新的基于 Smith 预估器的单神经元 PSD 自适应控制算法,即由 Smith 预估器和单神经元 PSD 自适应控制器组合的复合控制。并且利用Lyapunov 稳定性理论证明了单神经元自适应控制器的稳定性。实验结果表明,这种控制方式具有较好的自适应性和鲁棒性。展开更多
文摘This paper proposes a new concept of synthesized voltage vector to address dead-time effect issue for Finite Control Set Model Predictive Control(FCS-MPC)technique.For a voltage source inverter(VSI),dead-time is inevitably inserted between the turn off and turn on instants of power devices to avoid short circuit phenomenon.The influence of dead-time leads to output voltage vector error of three-phase inverters.Furthermore,it will result in computing deviation in cost function,and will deteriorate the performance of the system if not properly dealt with.In this paper,the problem is clearly analyzed,and the solution to this issue is proposed by introducing a synthesized voltage vector.The proposed solution is verified by Hardware-in-the-loop(HiL)test in real time,and results validate the effectiveness of the proposed solution.
文摘The key of speed sensorless vector control system lies in the accurate orientation of magnetic field. In some field-oriented algorithms, the integrator of observers and the dead-time effect bring in system errors during the estimation of field position. In this paper, a saturated feedback integrator is used, and the dead-time effect is compen- sated by current positive feedback. Experiments were carried out on the hardware platform of MCK2407, with chip TMS320LF2407 from TI Company. The results show that the prooosed method is simole and effective, and the accuracy of field position is improved.
基金Supported by the National Natural Science Foundation of China(61961016)the Natural Science Foundation of Hubei Province(2019CFB593)PhD Research Start-Up Foundation of Hubei Minzu University(MY2018B08)
文摘In the inverter circuit,there exists a specific on-off time in each power transistor.As such,to prevent a short circuit of the two switch devices on the upper and lower bridge arms,a specific dead time must be set in the pulse width modulation(PWM)and the sinusoidal pulse width modulation(SPWM)signals.In this paper,an intellectual property(IP)core that can introduce a high-precision dead time of arbitrary length into PWM or SPWM signals of the inverter is designed to increase the precision,convenience and generalization of dead time control,resulting in a boosted control accuracy of up to 10 ns.Moreover,the added Avalon bus enables IP cores to be accessed by the field programmable gate array(FPGA)processor in a standard manner and multiple IP cores of the same class can be easily incorporated.In addition,an application for setting and compensating for dead time in a three-phase inverter based on system on programmable chip(SOPC)technology is presented.With the Nios II CPU as its core,the system adopts the mean voltage compensation method to calculate the compensation voltage,and performs dead-time compensation in a feed-forward manner.The three dead-time IP cores are controlled by Avalon bus.These allow the dead time of three groups of power transistors to be accurately controlled and flexibly adjusted.The system also features the master computer communication function while boasting the advantages of flexible control,high precision and low cost.
基金supported by the National Natural Science Foundation of China(51577025)the Science and Technology Program of State Grid Corporation of China(5100-201999330A-0-0-00).
文摘Subsynchronous resonance(SSR)and high-frequency resonance(HFR)are two phenomena that exist in a doubly fed induction generator(DFIG)system operated in a weak grid.Besides the aforementioned resonance,dead-time in the converter(rotor side converter(RSC)and grid side converter(GSC))of the DFIG system can cause resonance at middle frequencies.The aforementioned resonance at middle frequencies can greatly degrade dynamic performance and cause instabilities in the DFIG system.Nevertheless,there is not enough research available in existing literature on resonance in the DFIG system,considering dead-time impact.This paper proposes a new method of resonance analysis in a DFIG system,taking dead-time effect into consideration and utilizing small-signal impedance modeling.Dead-time of the RSC and GSC will introduce distorted voltage into the rotor-and stator-side of the DFIG.Then,rotor-side impedance is modified by adding the effect of transfer function(impedance)from the distorted voltage to rotor current.Likewise,the stator-side impedance is modified by adding the effect of the transfer function(impedance)from distorted voltage to stator current.Thus,overall DFIG system impedance,as seen from the point of common coupling is changed.Finally,resonance is revealed by plotting the DFIG system impedance and weak grid impedance on the Bode plot.Additionally,resonance mitigation is impedance on the Bode plot.Additionally,resonance mitigation is exposed through the dead-time compensation(DTC)technique using an adaptive second-order bandpass filter.With the proposed technique,the resonance at middle frequencies is damped with zero probability of resonance reoccurrence.Finally,the validity and the accuracy of the proposed DTC techniques are validated using mathematical analysis and simulations in Matlab.
文摘针对电厂中主汽温控制系统具有大滞后、非线性的特点,提出了一种新的基于 Smith 预估器的单神经元 PSD 自适应控制算法,即由 Smith 预估器和单神经元 PSD 自适应控制器组合的复合控制。并且利用Lyapunov 稳定性理论证明了单神经元自适应控制器的稳定性。实验结果表明,这种控制方式具有较好的自适应性和鲁棒性。
