In contrast to most existing works on robust unit commitment(UC),this study proposes a novel big-M-based mixed-integer linear programming(MILP)method to solve security-constrained UC problems considering the allowable...In contrast to most existing works on robust unit commitment(UC),this study proposes a novel big-M-based mixed-integer linear programming(MILP)method to solve security-constrained UC problems considering the allowable wind power output interval and its adjustable conservativeness.The wind power accommodation capability is usually limited by spinning reserve requirements and transmission line capacity in power systems with large-scale wind power integration.Therefore,by employing the big-M method and adding auxiliary 0-1 binary variables to describe the allowable wind power output interval,a bilinear programming problem meeting the security constraints of system operation is presented.Furthermore,an adjustable confidence level was introduced into the proposed robust optimization model to decrease the level of conservatism of the robust solutions.This can establish a trade-off between economy and security.To develop an MILP problem that can be solved by commercial solvers such as CPLEX,the big-M method is utilized again to represent the bilinear formulation as a series of linear inequality constraints and approximately address the nonlinear formulation caused by the adjustable conservativeness.Simulation studies on a modified IEEE 26-generator reliability test system connected to wind farms were performed to confirm the effectiveness and advantages of the proposed method.展开更多
The EU, the United States and other economies, with the intention to implement unilateral trade measures Border Carbon Adjustments, impose emission reduction pressure on developing countries. Once implemented, the mea...The EU, the United States and other economies, with the intention to implement unilateral trade measures Border Carbon Adjustments, impose emission reduction pressure on developing countries. Once implemented, the measures will have great impact on China's foreign trade. Using the input-output table in 2007, this paper had analyzed the influences on China's foreign trade as a whole and sub-sectors in three tax rates scenarios. The results showed that the tariff level of China's exports will increase by 3.6%-6.3% if the tax was levied on exports embodied emissions, and by 1.0%-1.7% if levied on export direct emissions. In 2007, the former total amount of carbon tax was about US$42.6-73.0 billion, 4 times that of the latter. Based on export embodied emissions, sectors largely influenced were non-traditional energy intensive ones, such as textile, et al. These sectors should be encour-aged to carry out industrial upgrading, raising the value-added of export goods, and reducing their embodied emissions by reduction of energy intensity. Taking into account of the complexity of data collection, the tax levied on products direct emission is more operational. The results showed that the five top sectors most affected were other chemical materials, processing of petroleum and nuclear fuel, coking, smelting and rolling of ferrous metal and textile. Most of them were energy intensive sectors. Therefore, adjusting export products structure, and controlling too fast development of energy intensive industries are also important strategies in China.展开更多
This paper presents a super performance bandgap voltage reference for DC-DC converter with adjustable output. it generates a wide range of voltage reference ranging from sub- 1V to 1,221 7 V and has a low temperature ...This paper presents a super performance bandgap voltage reference for DC-DC converter with adjustable output. it generates a wide range of voltage reference ranging from sub- 1V to 1,221 7 V and has a low temperature coefficient of 2.3 × 10 ^5/K over the temperature variation using the current feedback and resistive subdivision. In addition, the power supply rejection ration of the proposed bandgap voltage reference is 78 dB. When supply voltage varies from 2.5 V to 6 V, output VREF is 1,221 685±0.055 mV.展开更多
基金State Grid Jiangsu Electric Power Co.,Ltd(JF2020001)National Key Technology R&D Program of China(2017YFB0903300)State Grid Corporation of China(521OEF17001C).
文摘In contrast to most existing works on robust unit commitment(UC),this study proposes a novel big-M-based mixed-integer linear programming(MILP)method to solve security-constrained UC problems considering the allowable wind power output interval and its adjustable conservativeness.The wind power accommodation capability is usually limited by spinning reserve requirements and transmission line capacity in power systems with large-scale wind power integration.Therefore,by employing the big-M method and adding auxiliary 0-1 binary variables to describe the allowable wind power output interval,a bilinear programming problem meeting the security constraints of system operation is presented.Furthermore,an adjustable confidence level was introduced into the proposed robust optimization model to decrease the level of conservatism of the robust solutions.This can establish a trade-off between economy and security.To develop an MILP problem that can be solved by commercial solvers such as CPLEX,the big-M method is utilized again to represent the bilinear formulation as a series of linear inequality constraints and approximately address the nonlinear formulation caused by the adjustable conservativeness.Simulation studies on a modified IEEE 26-generator reliability test system connected to wind farms were performed to confirm the effectiveness and advantages of the proposed method.
文摘The EU, the United States and other economies, with the intention to implement unilateral trade measures Border Carbon Adjustments, impose emission reduction pressure on developing countries. Once implemented, the measures will have great impact on China's foreign trade. Using the input-output table in 2007, this paper had analyzed the influences on China's foreign trade as a whole and sub-sectors in three tax rates scenarios. The results showed that the tariff level of China's exports will increase by 3.6%-6.3% if the tax was levied on exports embodied emissions, and by 1.0%-1.7% if levied on export direct emissions. In 2007, the former total amount of carbon tax was about US$42.6-73.0 billion, 4 times that of the latter. Based on export embodied emissions, sectors largely influenced were non-traditional energy intensive ones, such as textile, et al. These sectors should be encour-aged to carry out industrial upgrading, raising the value-added of export goods, and reducing their embodied emissions by reduction of energy intensity. Taking into account of the complexity of data collection, the tax levied on products direct emission is more operational. The results showed that the five top sectors most affected were other chemical materials, processing of petroleum and nuclear fuel, coking, smelting and rolling of ferrous metal and textile. Most of them were energy intensive sectors. Therefore, adjusting export products structure, and controlling too fast development of energy intensive industries are also important strategies in China.
文摘This paper presents a super performance bandgap voltage reference for DC-DC converter with adjustable output. it generates a wide range of voltage reference ranging from sub- 1V to 1,221 7 V and has a low temperature coefficient of 2.3 × 10 ^5/K over the temperature variation using the current feedback and resistive subdivision. In addition, the power supply rejection ration of the proposed bandgap voltage reference is 78 dB. When supply voltage varies from 2.5 V to 6 V, output VREF is 1,221 685±0.055 mV.
文摘针对电子产品电池高续航、电压可调、小型化的需求,设计了一款低纹波、输出电压可调的便携式直流电源,具备过温、过充、过放、过流保护功能,可直观显示电源剩余电量及输出电压值。提出了单芯片电源管理系统的新结构,包含A、B、C 3个模块。模块A是USB输出模块,模块B是可调输出模块,模块C是电源充电及管理模块。通过整合与集成,有效降低了便携式电源管理系统的开发及应用成本。为了验证电源设计的输出性能及充放电时电流与电压的稳定性,将一款常见的5 V 2 A规格的手机充电器与本设计进行对比测试,结果表明,除了电压输出稳定、纹波小等优点外,该设计还可根据使用场景的需求调节可调电阻的电阻值,满足不同的电压输出与功率要求,扩大了电源的使用范围。
