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 proposed method is simple and effective, and the accuracy of field position is improved.展开更多
Dead time is necessary for the coupled power switches to prevent shoot-through,especially in the modular multilevel converters(MMCs)with a large number of power switches.This paper proposes a dead-time effect suppress...Dead time is necessary for the coupled power switches to prevent shoot-through,especially in the modular multilevel converters(MMCs)with a large number of power switches.This paper proposes a dead-time effect suppression strategy for MMCs with nearest level modulation.The operational principles of MMCs are first analyzed.According to the operational features of MMCs,the method that removes a switching signal from the coupled switches and the reduced switching frequency voltage balancing algorithms(RSFVBAs)are mixed in the proposed method.In the intervals that are furthest away from the zerocrossing points(ZCP)of arm currents,the single switching signal method can completely eliminate the dead-time effect(DTE).Alternatively,the DTE is suppressed by the RSFVBA in intervals that are close to the ZCP.By the combination of the two methods,the dependence of the DTE suppression method on currents is reduced and the influences of ZCP are also released without degrading the normal operation performance of MMCs.Moreover,the output performance of MMCs is improved and the voltage stress on the arm inductor dramatically decreases.Finally,the validation of the method is verified by the simulation results with the professional tool Matlab/Simulink.展开更多
Although the dead-time optimization design of resonant converters has been widely researched,classical design methods focus more on achieving zero-voltage switching(ZVS)operation.The body diode loss is always ignored,...Although the dead-time optimization design of resonant converters has been widely researched,classical design methods focus more on achieving zero-voltage switching(ZVS)operation.The body diode loss is always ignored,which results in low-efficiency of the converter,especially,in energy router(ER).To deal with this problem,this paper proposes an adaptive deadtime modulation scheme for bidirectional LLC resonant converters in ER.First,the power loss of the MOSFET is analyzed based on the dead-time.Then,a novel dead-time optimization modulation principle is proposed.It can eliminate the body diode loss of MOSFET compared with existing literature.Based on the optimization modulation principle,this paper proposes an adaptive dead-time modulation scheme.To this end,the converter adopting the scheme no longer needs to calculate dead-time,which simplifies the parameter design process.Meanwhile,this scheme enables dead-time to dynamically change with working conditions according to the dead-time optimization modulation principle.With these effects,the ZVS operation is achieved,and the body diode loss of MOSFET is also eliminated.Furthermore,a digital implementation method is designed to make the proposed modulation scheme have fast-transient response.Finally,experimental results show that the proposed dead-time modulation scheme enables converters to achieve ZVS operation in all working conditions,and has higher efficiency than classical dead-time design methods.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
为了精确地反映死区时间对双有源桥式变换器(dual active bridge,DAB)移相角偏移与传输功率的影响,将缓冲电容的作用引入到DAB死区效应的分析中。通过设定最优死区时间将电感电流过零点排除在死区时段之外,降低了不同电压模式下死区过...为了精确地反映死区时间对双有源桥式变换器(dual active bridge,DAB)移相角偏移与传输功率的影响,将缓冲电容的作用引入到DAB死区效应的分析中。通过设定最优死区时间将电感电流过零点排除在死区时段之外,降低了不同电压模式下死区过程分析的难度,并得到一个更精确的DAB移相角与传输功率的模型。结果表明:应用该模型能够准确地计算出DAB任意工况下的静态工作点,从而提高DAB小信号建模的精度。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 proposed method is simple and effective, and the accuracy of field position is improved.
基金supported by the State Key Laboratory of Advanced Power Transmission Technology(GEIRI-SKL-2020-011)。
文摘Dead time is necessary for the coupled power switches to prevent shoot-through,especially in the modular multilevel converters(MMCs)with a large number of power switches.This paper proposes a dead-time effect suppression strategy for MMCs with nearest level modulation.The operational principles of MMCs are first analyzed.According to the operational features of MMCs,the method that removes a switching signal from the coupled switches and the reduced switching frequency voltage balancing algorithms(RSFVBAs)are mixed in the proposed method.In the intervals that are furthest away from the zerocrossing points(ZCP)of arm currents,the single switching signal method can completely eliminate the dead-time effect(DTE).Alternatively,the DTE is suppressed by the RSFVBA in intervals that are close to the ZCP.By the combination of the two methods,the dependence of the DTE suppression method on currents is reduced and the influences of ZCP are also released without degrading the normal operation performance of MMCs.Moreover,the output performance of MMCs is improved and the voltage stress on the arm inductor dramatically decreases.Finally,the validation of the method is verified by the simulation results with the professional tool Matlab/Simulink.
文摘Although the dead-time optimization design of resonant converters has been widely researched,classical design methods focus more on achieving zero-voltage switching(ZVS)operation.The body diode loss is always ignored,which results in low-efficiency of the converter,especially,in energy router(ER).To deal with this problem,this paper proposes an adaptive deadtime modulation scheme for bidirectional LLC resonant converters in ER.First,the power loss of the MOSFET is analyzed based on the dead-time.Then,a novel dead-time optimization modulation principle is proposed.It can eliminate the body diode loss of MOSFET compared with existing literature.Based on the optimization modulation principle,this paper proposes an adaptive dead-time modulation scheme.To this end,the converter adopting the scheme no longer needs to calculate dead-time,which simplifies the parameter design process.Meanwhile,this scheme enables dead-time to dynamically change with working conditions according to the dead-time optimization modulation principle.With these effects,the ZVS operation is achieved,and the body diode loss of MOSFET is also eliminated.Furthermore,a digital implementation method is designed to make the proposed modulation scheme have fast-transient response.Finally,experimental results show that the proposed dead-time modulation scheme enables converters to achieve ZVS operation in all working conditions,and has higher efficiency than classical dead-time design methods.
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.
文摘为了精确地反映死区时间对双有源桥式变换器(dual active bridge,DAB)移相角偏移与传输功率的影响,将缓冲电容的作用引入到DAB死区效应的分析中。通过设定最优死区时间将电感电流过零点排除在死区时段之外,降低了不同电压模式下死区过程分析的难度,并得到一个更精确的DAB移相角与传输功率的模型。结果表明:应用该模型能够准确地计算出DAB任意工况下的静态工作点,从而提高DAB小信号建模的精度。
