16 International Conference on Manufacturing Science and Information Engineering (ICMSIE 16) ISBN: 978-1-6595-35- Research on H-Bridge DC Energy Router In the Energy Internet SHAOXIA CHEN, GANG YAO, IDAN ZHO, HAJN Y and ZHIZH YIN ABSTRACT H-bridge DC energy router values much in scientific research considering its important role-playing in the process of energy flow. The content of this thesis is as follows: Firstly, it introduces the research situation, system structure, control strategy of energy internet; and then, elaborates the concept and operating principle of H-bridge DC energy router; finally, the simulation and experimental platform of H-bridge DC energy router were established. Based on the analysis and experimental results, it is verified that the H-bridge DC energy router used in energy internet has feasibility. INTRODCTION In order to solve the problem of global energy crisis and environmental pollution, global energy internet becomes a new boom in the development of electric power industry [1]. In 8, Germany proposed the concept of E-Energy and energy internet plan []. In the same year, nited States NFS established the FREEDM system center, proposed the concept of energy router, and conducted prototype implementation [3], [4]. In July 14, Chairman of the State Grid Corporation proposed through the inner continent, continental and global grid interconnection, optimize the allocation of global energy resource in the Institute of Electrical and Electronics Engineers (IEEE) power and energy society. Shaoxia Chen, Shanghai niversity of Electric Power,Shanghai, China Gang Yao,idan Zhou, Huajun Yu, Zhizhu Yin,Ministry of Education Key aboratory of Control of Power Transmission and Conversion, Shanghai Jiao Tong niversity 11
Energy consumption can be more efficient by interchange between electric power, thermal and chemical power [5], [6]. Although electricity is a kind of all energy in the energy of the internet, but electricity has obvious advantage in energy transmission efficiency and so on. The body of the future energy infrastructure in transmission is still the power grid. Therefore, the energy internet actually is a new power structure based on the concept of internet, which takes grid power as the backbone and micro-grid as the local area network. Power of the energy internet can be transformed and consumed by energy routers. However, the references [3], [4], [7] didn t raise relevant energy coordinated control strategy for energy internet, also, lack of simulation and experimental analysis. Based on the above issues, this paper gives a model structure of regional energy internet based on the H-bridge DC energy router. Also, the concept, principal, topology and the process of deduction of the H-bridge DC energy router are analyzed. Then, the feasibility of the H-bridge DC energy router can be used for energy internet and can achieve bidirectional energy share are verified in this text by the simulation of PSCAD and related experiment. STRCTRE ANAYSIS AND CONTRO STRATEGY In order to solve the energy access, control and transmission problems of the energy internet, the concept of energy router is proposed [3]. The energy router is a multi-port equipment, composed of power electronic device, software, CP and network interfaces. Since the H-bridge DC energy router has a much wider applicability than traditional router, a model structure of regional energy internet based on the H-bridge DC energy router is proposed. ocal area network Information exchange Wind Pv Gas turbine Diesel engine Hydrogen Energy flow Regional Energy Network Energy Network AC/DC AC/DC AC/DC H-bridge High voltage power grid AC grid AC/DC 6V H-bridge H-bridge H-bridge DC/AC Energy Network Energy Storage Electric Vehicle DC load AC load Figure 1. The structure of regional energy internet. 1
Figure. 1 shows the structure of regional energy internet based on the H-bridge DC energy router. The structure includes: distributed energy, H-bridge DC energy routers, traditional routers, energy storage and load cells and so on. The part of dashed frame can be seen as a regional energy network. Power of the distributed energy flows into the regional energy networks through the energy router, thus, formed a comprehensive and diversified regional energy networks. Global energy internet can be realized by interconnection of multiple regional energy networks. WORKING PRINCIPE OF THE ENERGY ROTER H-bridge DC energy routers generally working in unidirectional mode (buck, boost, buck/boost) or bi-directional mode (buck-boost, buck/boost), taking into account that the unidirectional mode and the traditional buck or boost circuit works consistency, this article will focus on bi-directional flow of energy makes depth discussions, as shown in Figure.. i1 Energy flow i i1 i Energy flow i1 Energy flow i S1 D1 S3 D3 in C1 C dc in S1 D1 S3 D3 C1 C dc S1 D1 S3 D3 in C1 C dc S D S4 D4 S D S4 D4 S D S4 D4 (a) Bi-directional boost mode of buck-boost (b) Bi-directional step-down mode of buck-boost (c) Bi-directional mode of buck/boost Figure. Operating modes of H-bridge DC energy router. Set dc as the DC bus voltage, in is the input voltage, is the inductance voltage, t is the inductance current, on is the switch break over time, D is the Switch duty cycle, I is the increment of current, M is the voltage gain of router. In Figure. (a), the router works at bi-directional boost mode. When the energy S flow is positive-going, 1 keeps on, S4 is switching on a certain frequency, S and S 3 keep off. When S 4 is on, the inductance begin to storage energy and the current increase. The flow ways of the current can be indicated by the blue solid line: di dt I t in (1) on 13
i I ton () When S 4 is off, the inductance begin to storage energy through D 3. The flow ways of the current can be indicated by the blue dashed line: By the formula (), (4): di I dt T t dc in I ( T ton) (4) in dc (3) on dc T 1 M1 (5) in 1 ton 1 D When energy flow is reversed, S 3 keeps on, S is switching on a certain frequency, S1 and S 4 keep off. When S is on, the flow ways of the current can be indicated by the red solid line. When S is off, the flow ways of the current can be indicated by the red dashed line. The energy router can achieve bi-directional boost requirement of 1V to 4V when D =.75. In Figure. (b), by the same token: M dc D (6) in The energy router can achieve bi-directional buck requirement of 8V to 4V when D =.5. In Figure. (c), by the same token: dc D M 3 (7) in 1 D The energy router can achieve bi-directional boost requirement of 38V to 4V when D =.518. Through the analysis and comparison, it concludes that the bi-directional buck/boost mode of the H-bridge DC energy router has more extensive applicability. It not only meets the high buck-boost ratio requirements, but also reduces the requirements of the switch tube when both ends of the voltage is similar to each other. 14
SIMATION ANAYSIS Figure.3 shows the block diagram of H-bridge DC energy router in simulation and control. The energy router works at bi-directional buck/boost mode at the moment. sing the PSCAD software, the simulation model of H-bridge DC Energy router is established and analyzed. i1 Positive power i Rin in S1 Reverse power D1 S3 C1 out 1 S D S4 D4 D3 C Rout 4 413 1 386.1 1 Selector Switch outref + out PI I ref + I Triangular carrier - PWM PI + Figure 3. The block diagram of H-bridge DC energy router in simulation and control. In this simulation, the expression of the input transmission power is: 1 1 i1 Rin P i (8) The expression of the output transmission power is: P 4 Rout out out (9) When P 413V or 386.1V. is a constant value and P = 5369 W, the solution of out outref equals to Therefore, the reference voltage has 4V, 413V and 386.1V three options signal. The double close loop framework is applied in the PFC control outref circuit. During 1~s, =4V, =A, there is no energy flow. During.5~1.5s, outref =413V, outref, the energy flow is positive-going. During 1.5~s, i =386.1V,, the energy flow is reversed. 15
output voltage (A) Input Current(A) Input voltage (kv) Output voltage (V) Onput voltage (kv) Inductor Current (A) Inductor Current (A) Inductor Current (A) In Figure 3, change the value of 1, make the simulation runs in three situations, when 1 is 1V, 3V or 38V. In the case of three kinds of voltage, the transmission power of input is equal to the transmission power of output approximately. The simulation wave-forms of, out and are shown in Figure 5. Main : 1V-4V I 15 1 5-5 -1-15 - out.44.4.4.38.36 I1 1 75 5 5-5 -5-75 t(s).5 1. 1.5. Input Current( A) Main : 3V-4V 1 5-5 -1-15 out.44.4.4.38.36 I1 45 3 15-15 -3-45 t(s).5 1. 1.5.......... Main : 38V-4V 1 75 5 5-5 -5-75 out.44.4.4.38.36 I1 3 15-15 -3-45 t(s).5 1. 1.5.......... (a) 1 =1V(b). 1 =3V(c). 1 = 38V Figure 4. Waveforms of inductor current, output voltage and input current under the different modes. With the decrease of the voltage difference on 1 and, and i1 are reduced. The inductance current ripple is larger when 1 is close to, means D =.5, as shown in Figure 4. EXPERIMENTA CONFIRMATION In this paper, in order to verify the feasibility of the H-bridge DC energy router, corresponding experimental platform is set up according to the Figure 3. The work-state of the energy transmission of input and output is shown in Figure 5 (a)..4s, changes from A to 3A, the energy flow is positive-going..8s, Duty ratio changes, changes from 3A to -3A, the energy flow is reversed. Figure 5 (b) corresponds to the energy transfer from input to the output, changes from A to 3A, and the energy flow is positive-going. Figure 5 (c) corresponds to the energy transfer from output to the input, changes from A to -3A, and the energy flow is reversed. Figure 7 is the steady amplification waveform when equals to 3A, and the ripple of is 1A. 16
(a) (b) (c). Figure 6. Waveforms of circuit changes when voltage reversal. Figure 7. Steady-state amplified waveform when the inductor current is 3A. CONCSION Efficient and controllable energy router is an important factor in promoting the rapid development of energy internet. This paper has presented a comprehensive overview of the H-bridge DC energy router. The result of simulation and related experiment shows that H bridge DC energy routers can realize power's bi-direction flow. The intended contribution of this work is to identify the feasibility of the H bridge DC energy routers can be used in the energy internet. Currently, energy router and large-capacity energy storage technology is not mature yet, energy management systems and related standards need to be improved. In the future we still need to solve many problems before the energy internet began to spread. REFERENCES 1. Siebel, Thomas M. The Internet of Energy [J]. Electric Perspectives, 15, Vol.4 (), pp.54,56-57.. Federal Ministry of Economics and Energy of Germany [EB/O]. [13-6-6]. E-Energy projiect official website:http://www.e-energy.de/en/index.phd. 3. HANG A Q, CROW M, HEYDY G T, et.al. The futrure renewable electric energy delivery and management(freedem) systerm: the energy internet [J]. Renewable and Sustainable Energy Review, 11,15:4348-4356. 17
4. Xu Y, Zhang J, Wang W, et al. Energy router: architectures and functionalities toward energy internet. In: Proceedings.of IEEE International Conference on Smart Grid Communications, Brussels, 11. 31 36 5. asseter R H. Microgrids. In: Proceedings of IEEE Power Engineering Society Winter Meeting, Michigan,.35 38 6. Xu Y, Zhang J, Wang W, et al. Energy router: architectures and functionalities toward energy internet. In: Proceedings.of IEEE International Conference on Smart Grid Communications, Brussels, 11. 31 36 7. Massoud A S, Wollenberg B F. Toward a smart grid: power delivery for the 1st century. IEEE Power Energy M,5, 3: 34 41 8. John Schonberger, Richard Duck, Simon D. DC-bus signaling: A distributed control strategy for a Hybrid Renewable Nanogrid [J]. IEEE Transactions on Industrial Electronics, 6, 53(5): 1453-146. 9. ee. Jun-Young Y Han, Byung Moon Moon, Nam-sup S. DC micro-grid operational analysis with detailed simulation model for distributed generation [C]. Energy Conversion Congress and Exposition (ECCE), 13:53-316. 18