At 18:00 onthe evening of June 29, 2023, the Heng Ai Jing Cheng team successfully held the12th paper reading activity of this school year. This activity was held in theacademic conference center, five first-year graduate students gave reports onrelevant literature, Mr. Chen Qiang and Mr. Li Fei served as the instructors ofthis paper reading, and some first-year graduate students attended the paperreading activity.
Fig.1 Photo of the paper reading activity
First of all, Zhou Pengzheng gave a report, and thetopic of the reading was "Analysis of Power Coupling Mechanism of VirtualSynchronous Generator and Improved Decoupling Control". Aiming at thepower coupling problem of VSG, this paper proposes a power decoupling control(QVPDC) method based on q-axis voltage drop that ignores the d-axis voltagedrop on the virtual inductor. The report first introduces the basic principlesof VSG and derives the power expression from the controlled small-signal model.Then, the conditions for power decoupling are obtained through analysis, and amethod for QVPDC is proposed.
During the teacher evaluation stage, Mr. Chen Qiangpointed out that the definition of virtual inductance here is inaccurate anddoes not meet the definition of inductor. Mr. Li Fei pointed out that intheory, pure inductibility will solve the problem of power coupling, but in theliterature, the power angle angle is 0 on the basis of pure sensibility, andthe method is not accurate enough; In addition, the experimental display showsthat the parameter setting needs to be moderate, and the experimental resultsare not completely decoupled, and the method proposed in this paper needs to beverified.
Fig. 2 Zhou Pengzheng acted as the reporter ofpaper reading
Secondly, Qian Feng gave a report, and the topic ofthe paper was "Research on the Transient Angular Stability of ParallelSynchronous and Virtual Synchronous Generators of Island Microgrid". Thispaper proposes an improvement method for the transient instability of asynchronous generator and a virtual synchronous generator parallel system. Thereport first starts from the difference between a synchronous generator and avirtual synchronous generator parallel system and two virtual synchronousgenerators, and points out the reasons why the former is prone to transientinstability. Then, according to the instability mechanism, an improved controlmethod is proposed, and the stability is evaluated by the Lyapunov function.
In the teacher's comment stage, Mr. Li Fei pointedout that the translation of the parallel system was not accurate enough, and itis still debatable whether the transient power angle characteristic analysis ofthe power system is applicable here. Mr. Chen Qiang asked questions about theinnovation of the paper and pointed out whether the method of evaluatingstability of the Lyapunov function is universal.
Fig. 3 Qian Feng acted as the reporter of paperreading
Then Xu Shusheng gave a report with the title:"Improving the Active Power Frequency Loop of Virtual SynchronousGenerator to Improve System Transient Stability". This paper aims at theproblem of power angle stability in VSG transient process under major systemfailures. Firstly, the idea of improving transient stability is obtained byanalyzing the power angle characteristic curve of VSG, and then theconventional VSG control is modified, and additional power loops and auxiliaryinertia links are added to the active circuit of VSG, so that the problem canbe solved.
In the stage of teacher commentary, Mr. Chen Qiangfirst pointed out that in the paper reading activity, attention should be paidto sorting out the context of the article, rather than simply elaborating on thecontent. Subsequently, Mr. Li Fei pointed out that the applicability of theequal area principle method applied in the paper needs to be considered here.
Fig. 4 Xu Shusheng acted as the reporter of paperreading
Then Li Haiyang read the paper with the title:"Transient Damping Method to Improve the Synchronous Stability of VirtualSynchronous Generator". This paper mainly studies how to avoid theconflict between the synchronous stability and inertial response of VSG, andimprove the synchronization stability and frequency stability of the system.Firstly, Li Haiyang analyzed the synchronous stability of the quasi-synchronousgenerator, and concluded that it is necessary to analyze the equilibrium pointafter disturbance and limit the power angle to improve the stability. It isthen pointed out that a method of introducing transient damping to improvestability is proposed.
During the teacher's comment stage, Mr. Chen Qiangasked what the actual meaning of transient damping is. Subsequently, Mr. Li Feipointed out how to set the inertia of the power grid in the experiment so asnot to affect the inertia test of VSG, and pointed out whether the generalizedinertia proposed by Xu Haizhen's thesis has reference value for this paper.
Fig. 5 Li Haiyang acted as the reporter of paperreading
Finally, Wang Haobin read the paper with the title:"A Virtual Synchronous Generator Adaptive Control Strategy". Thispaper mainly studies the inhibition effect of moment of inertia and dampingcoefficient on the oscillation of the output power and output frequency of VSGunder the condition of large power fluctuations in the distribution network.Firstly, the influence of moment of inertia and damping coefficient on the VSGpower step response process is introduced, and then an adaptive controlstrategy is proposed for this effect. The adaptive control strategy canmaintain the optimal damping ratio under the premise of ensuring short responsetime and small overshoot.
In the stage of teacher comment, Mr. Li Fei pointedout that the article was published too early, and the article with a morerecent year should be selected as much as possible to read the paper, and alsoasked questions about the adaptive strategy of the article.
Fig. 6 Wang Haobin acted as the reporter of paperreading
In this paper reading activity, 5 first-yearstudents gave wonderful sharing, and Mr. Chen Qiang and Mr. Li Fei gavemeticulous guidance, which not only gained knowledge, but also strengthened theestablishment method of scientific research ideas, and deepened the ability toanalyze and think about the applicability of the program. With the support ofteachers and students, the paper reading activity ended successfully.
Editor:Qian Feng | Photographer: Qian Feng