Current Sharing Temperature Test and Simulation with GANDALF Code for ITER PF2 Conductor Sample

Cable-in-conduit conductor （CICC） conductor sample of the PF2 coil for ITER was tested in the SULTAN facility. According to the test results, the CICC conductor sample exhibited a stable performance regarding the current sharing temperature. Under the typical operational conditions of a current of 45 kA, a magnetic field of 4 T and a temperature of 5 K for PF2, the test result for the conductor current sharing temperature is 6.71 K, with a temperature margin of 1.71 K. For a comparison thermal-hydraulic analysis of the PF2 conductor was carried out using GANDALF code in a 1-D model, and the result is consistent with the test one.

Current Sharing Analysis of Arm Prototype for ITER PF Converter Bridge

A bridge arm prototype of ITER poloidal field （PF） converter modules has been designed and fabricated. Non-cophase counter parallel connection is chosen as the arm structure of the prototype. Among all factors affecting current sharing, arm structure is the main one. During the design of the arm prototype, a novel method based on inductance matrixes is employed to improve the current sharing of the bridge arm. The test results on the prototype show that the current sharing performance of the arm prototype is much better than relevant design requirement, and that the matrix method is very effective to analyze and solve the current sharing problems of thyristor converters.

An Improvement on Current Sharing Characteristics of Poloidal Field (PF) AC-DC Converters

In response to the current imbalance phenomenon and its harmfulness, a current sharing circuit model is built up, which reveals the underlying causes for the current imbalance through a quantitative analysis. Then, a feasible approach of improvement, namely enlargement of the length of connection busbars, is proposed. After the amendment, it can be seen that the current sharing coefficient is ahnost unity under rated or fault current conditions.

Input-parallel output-parallel configuration of boost half bridge DC-DC converter with control strategy

The concept of connecting two boost half bridge DC-DC converter modules in input-paral- lel output-parallel configuration is presented. The input-parallel-output-parallel （IPOP） converter consists of multiple boost half bridge （BHB） DC-DC converter modules which are connected in par- allel at the input and output side. This kind of converter is an attractive solution for high power ap- plications. The correlation between input current sharing （ICS） and output current sharing （OCS） of the IPOP converter basic modules is described. Two loop control strategies, consisting of input cur- rent loop and output voltage loop, have been developed to achieve equal ICS and OCS in this present work. The control strategy for the IPOP configuration of boost haft bridge DC-DC converter has been verified for different load conditions （half load and full load）, The IPOP system proposed here is comprising of two modules but it can be extended to three or more. The performance of the pro- posed system along with the control strategy is verified by simulation in MATLAB using Simpower tool. Finally the satisfactory simulation results are obtained.

Test and Analysis of China's First Short Conductor Sample for ITER Toroidal Field Coils

In the flamework of the ITER qualification tests, the first China TF conductor sample （CNTF1） was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal stannum strands provided by the Oxford ~upercon- cluctlng technology company （OST）. In order to evaluate the conductor performance, the current sharing temperature （Tcs） was measured at specified electromagnetic load cycling steps. Both conductor sections of the CNTF1 sample showed identical performance. Tcs was 7.2 K before cycling loading, and 6.9 K even after 950 cycles, without significant degradation, which substan- tially exceeds the ITER requirement of 5.7 K. The tests of the CNTF1 conductor sample showed that the electromagnetic cyclic load exhibited a negligible effect on the conductor performance. The coupling time constant 0 for AC loss was 214 ms and 71.52 nrs before and after the cycling load. respectively. The test results of the sample are compared with the strand performance and parameter model analysis.

Input series out putparallel based multi-modular boost half bridge DC-DC converter with a dynamic control scheme

Multi-modular system plays an important role in power system architecture because low voltage and low power converters can be connected in any combination parallel or series at input/ output side in order to obtained any given power system specifications. Multi-modular boost haft bridge DC-DC converter in the configuration of input series output parallel has been investigated in this paper. The boost half bridge DC-DC converters are connected in input series output parallel con- figuration in order to achieve equal input voltage sharing and output current sharing between the con- verters. This can be achieved with the help of dynamic control scheme which consists of two loops, a voltage loop and a current loop, for each module. Dynamic behavior of multi-modular converter configuration has been observe by varying the load condition. Moreover, the results obtained through multi-modular converter describe that the system has good dynamic and steady state response. Al- though two converter modules are focused in this paper but it can be modified to any number of modules.

Decoupling Control Strategy for Single Phase SPWM Parallel Inverters

A deconpling control strategy of inverter parallel system is proposed based on the equivalent output impedance of single phase voltage source SPWM （sinusoidal pulse width modulation） inverter. The active power and reactive power are calculated in terms of output voltage and current of the inverter, and sent to the other inverters in the parallel system via controller area network （CAN） bus. By calculating and decoupling the circumfluence of the active power and reactive power, the inverters can share load current via the regulation of the reference-signal phase and amplitude. Experimental results of an 110V/2kVA inverter parallel system show the feasibility of the decoupling control strategy.

Proportional Current Sharing Based on Periodic Dynamic Event-driven H_(∞) Consensus in DC Microgrids with Power Coupling

Although the proportional current sharing has been widely studied,the heterogeneous characteristic of the different interfaced converters and power coupling terms among distributed generators(DGs)are rarely considered.Therefore,this paper proposes a secondary H_(∞)consensus method with a periodic dynamic event-driven scheme for dc microgrids with power coupling to accomplish the precise proportional current-sharing.It is useful for reducing carbon.First,a generalized converter is constructed through equivalent transformation between rectifier and boost converter.Moreover,the heterogeneous characteristic of the interfaced converters regarding different DGs,such as wind and solar generators,is embedded into controller design.Furthermore,the standard linear heterogeneous multi-agent system with power coupling term is built.On this basis,the problem of proportional current sharing is modified into the output consistency problem of multi-agent systems.Furthermore,the H_(∞)consensus approach is proposed to accomplish the precise proportional current sharing.Meanwhile,to shorten communication bandwidth,the periodic dynamic event-driven communication strategy is designed.Compared with traditional event-driven communication schemes,a lower communication frequency has been obtained through the proposed communication scheme.In addition,this communication scheme not only avoids Zeno-behavior,but also acquires the smallest sampling time interval.Finally,effectiveness of the proposed approach is verified by two test systems.