To solve the problem of circulating power of dual active bridge(DAB)DC-DC converter over a wide voltage conversion ratio,this paper proposes a novel synchronous PWM(S-PWM)modulation.Existence of circulating power incr...To solve the problem of circulating power of dual active bridge(DAB)DC-DC converter over a wide voltage conversion ratio,this paper proposes a novel synchronous PWM(S-PWM)modulation.Existence of circulating power increases current stress of devices and decreases efficiency,especially under light load conditions.Several modulation methods have been proposed to overcome the problem.They can reduce or eliminate either input or output side circulating power.In contrast,S-PWM not only eliminates both sides circulating power and reduces current stress,but also achieves zero-current-switching(ZCS)turn-on for all switches and ZCS turn-off for most across the full power range.No auxiliary or snubber circuits are increased.In addition,the control can be simplified so the transmitted power is related to only one variable.The S-PWM has four cases under different gain and power conditions.The detailed operation principle and modes of DAB under S-PWM are analyzed in the paper.In addition,four modulations in literature are discussed,and corresponding comparative analyses with S-PWM are given.Finally,a laboratory prototype is built to verify advantages and effectiveness of the proposed modulation.展开更多
Base on dynamic analysis for a Front Wheel Assist (FWA) tractor, a method of calculating and analyzing on the critical angle of steering for a FWA tractor is described in this paper. The mathematical model is also est...Base on dynamic analysis for a Front Wheel Assist (FWA) tractor, a method of calculating and analyzing on the critical angle of steering for a FWA tractor is described in this paper. The mathematical model is also established here. The critical steering angle which is a important parameter affecting the steering performance for a FWA tractor is defined in the article.展开更多
In 2006, except the basic improvement on HL-2A tokamak control system, data acquisition and processing system, a series of research activities have been developed in computer and control division. They include the con...In 2006, except the basic improvement on HL-2A tokamak control system, data acquisition and processing system, a series of research activities have been developed in computer and control division. They include the construction of the high performance computer （HPC） system, the plasma configuration real-time reconstruction with EFIT code, the immigration of plasma simulation codes, the improvement of the poloidal field control system with circulating current, the design of the new data acquiring device with higher anti-disturbing power, the new software on soft X-ray spectrum measurement providing the multi-channel Te evolution, the upgrade to the HL-2A data storage system and experimental net. On the other hand, according to the arrangement of HL-2A modification project, a series of designs such as new plasma configuration, poloidal field coils distribution and plasma shape and position control system are on the processing.展开更多
文摘To solve the problem of circulating power of dual active bridge(DAB)DC-DC converter over a wide voltage conversion ratio,this paper proposes a novel synchronous PWM(S-PWM)modulation.Existence of circulating power increases current stress of devices and decreases efficiency,especially under light load conditions.Several modulation methods have been proposed to overcome the problem.They can reduce or eliminate either input or output side circulating power.In contrast,S-PWM not only eliminates both sides circulating power and reduces current stress,but also achieves zero-current-switching(ZCS)turn-on for all switches and ZCS turn-off for most across the full power range.No auxiliary or snubber circuits are increased.In addition,the control can be simplified so the transmitted power is related to only one variable.The S-PWM has four cases under different gain and power conditions.The detailed operation principle and modes of DAB under S-PWM are analyzed in the paper.In addition,four modulations in literature are discussed,and corresponding comparative analyses with S-PWM are given.Finally,a laboratory prototype is built to verify advantages and effectiveness of the proposed modulation.
文摘Base on dynamic analysis for a Front Wheel Assist (FWA) tractor, a method of calculating and analyzing on the critical angle of steering for a FWA tractor is described in this paper. The mathematical model is also established here. The critical steering angle which is a important parameter affecting the steering performance for a FWA tractor is defined in the article.
文摘In 2006, except the basic improvement on HL-2A tokamak control system, data acquisition and processing system, a series of research activities have been developed in computer and control division. They include the construction of the high performance computer （HPC） system, the plasma configuration real-time reconstruction with EFIT code, the immigration of plasma simulation codes, the improvement of the poloidal field control system with circulating current, the design of the new data acquiring device with higher anti-disturbing power, the new software on soft X-ray spectrum measurement providing the multi-channel Te evolution, the upgrade to the HL-2A data storage system and experimental net. On the other hand, according to the arrangement of HL-2A modification project, a series of designs such as new plasma configuration, poloidal field coils distribution and plasma shape and position control system are on the processing.
