风电系统的稳定性对电网安全十分重要,提高风电并网的稳定性依然是当今研究的热点所在。针对永磁直驱风电系统的强耦合以及系统投运后网侧、机侧的波动问题。本文首先分析了永磁直驱风电系统的数学模型和暂态特性;然后在电压环引入一阶...风电系统的稳定性对电网安全十分重要,提高风电并网的稳定性依然是当今研究的热点所在。针对永磁直驱风电系统的强耦合以及系统投运后网侧、机侧的波动问题。本文首先分析了永磁直驱风电系统的数学模型和暂态特性;然后在电压环引入一阶线性自抗扰控制器LADRC(linear active disturbance rejection controller),以其代替传统PI控制器;再通过李雅普诺夫理论分析了采用一阶LADRC时系统的稳定性,得出系统在工程意义上是稳定的。最后,在Matlab/Simulink数字平台进行了仿真测试。多工况下的仿真结果表明,该改进方法与PI控制器相比,具有更优的快速性和抗扰性。展开更多
为了在可变温度和辐照条件下能够对光伏发电系统进行有效的最大功率点跟踪MPPT(maximum power point tracking),提出了一种针对变环境参数条件下MPPT优化控制的新方法。首先确定最优工作电压与外界环境参数之间的数学表达式;然后根据其...为了在可变温度和辐照条件下能够对光伏发电系统进行有效的最大功率点跟踪MPPT(maximum power point tracking),提出了一种针对变环境参数条件下MPPT优化控制的新方法。首先确定最优工作电压与外界环境参数之间的数学表达式;然后根据其非线性关系,建立了MPPT控制策略,该非线性关系可以对太阳能电池的辐照和温度变化做出快速响应;最后,通过Matlab/Simulink数值模拟仿真,验证了该控制算法即使在太阳辐射较低的情况下也能有效地实现光伏发电系统的MPPT。展开更多
Submersible electrical motor direct-drive progressing cavity pump (PCP) rodless lifting was studied to solve the traditional rod-drive pump problems, such as rod-tubing wearing, low efficiency and short running time. ...Submersible electrical motor direct-drive progressing cavity pump (PCP) rodless lifting was studied to solve the traditional rod-drive pump problems, such as rod-tubing wearing, low efficiency and short running time. The theoretical researches and laboratory experiments of key tools such as submersible motor and the construction technology of lifting system were introduced. The field application and economic benefit were analyzed and compared with the traditional rod pumping unit. A new low speed and large torque permanent magnet synchronous motor was developed. This motor was used to drive PCP without gear reducer, which improved the reliability and feasibility. It can run at the speed from 50 to 500 r/min with stepless speed regulation, and it can perform high efficiency and large torque. Besides, other key supporting tools, such as motor protector and flex shaft, were developed. The submersible electrical motor direct- drive PCP technology can be used in a 139.7 mm (5.5 in) casing well, with daily output ranging from 5 to 50 m3. Until now, the technology has been deployed more than 100 wells. The field application results show that it eliminates the rod-tubing wearing and saves electric energy by more than 30% compared with the traditional rod pumping unit. And it also makes the oil produced in a safe and environmental friendly way.展开更多
The global energy market is volatile at present.It is of great significance for the BRICS countries,representatives of emerging economies and energy powers in the world,to deepen practical cooperation in energy.With a...The global energy market is volatile at present.It is of great significance for the BRICS countries,representatives of emerging economies and energy powers in the world,to deepen practical cooperation in energy.With a large energy volume and obvious complementary advantages in energy resources,industries and technologies,the BRICS countries have a good basis and prospects for cooperation.With the continuous deepening of the BRICS cooperation mechanism,the mechanism for BRICS cooperation in energy has further improved and the path has become clear.In this paper,the history of BRICS energy cooperation mechanism,as well as the status quo and characteristics of BRICS energy cooperation are presented.From both internal and external dimensions,an in-depth analysis of the opportunities and challenges in energy cooperation among BRICS countries under the complex international situation is made,and strategic recommendations in four aspects are provided:to strengthen diversified cooperation and strategic alignment,to intensify information sharing and policy coordination,to improve financial security and settlement systems,and to promote the construction of“BRICS+”and cooperation mechanisms.展开更多
文摘风电系统的稳定性对电网安全十分重要,提高风电并网的稳定性依然是当今研究的热点所在。针对永磁直驱风电系统的强耦合以及系统投运后网侧、机侧的波动问题。本文首先分析了永磁直驱风电系统的数学模型和暂态特性;然后在电压环引入一阶线性自抗扰控制器LADRC(linear active disturbance rejection controller),以其代替传统PI控制器;再通过李雅普诺夫理论分析了采用一阶LADRC时系统的稳定性,得出系统在工程意义上是稳定的。最后,在Matlab/Simulink数字平台进行了仿真测试。多工况下的仿真结果表明,该改进方法与PI控制器相比,具有更优的快速性和抗扰性。
文摘为了在可变温度和辐照条件下能够对光伏发电系统进行有效的最大功率点跟踪MPPT(maximum power point tracking),提出了一种针对变环境参数条件下MPPT优化控制的新方法。首先确定最优工作电压与外界环境参数之间的数学表达式;然后根据其非线性关系,建立了MPPT控制策略,该非线性关系可以对太阳能电池的辐照和温度变化做出快速响应;最后,通过Matlab/Simulink数值模拟仿真,验证了该控制算法即使在太阳辐射较低的情况下也能有效地实现光伏发电系统的MPPT。
基金Supported by the PetroChina Science and Technology Project(2016B-4104)
文摘Submersible electrical motor direct-drive progressing cavity pump (PCP) rodless lifting was studied to solve the traditional rod-drive pump problems, such as rod-tubing wearing, low efficiency and short running time. The theoretical researches and laboratory experiments of key tools such as submersible motor and the construction technology of lifting system were introduced. The field application and economic benefit were analyzed and compared with the traditional rod pumping unit. A new low speed and large torque permanent magnet synchronous motor was developed. This motor was used to drive PCP without gear reducer, which improved the reliability and feasibility. It can run at the speed from 50 to 500 r/min with stepless speed regulation, and it can perform high efficiency and large torque. Besides, other key supporting tools, such as motor protector and flex shaft, were developed. The submersible electrical motor direct- drive PCP technology can be used in a 139.7 mm (5.5 in) casing well, with daily output ranging from 5 to 50 m3. Until now, the technology has been deployed more than 100 wells. The field application results show that it eliminates the rod-tubing wearing and saves electric energy by more than 30% compared with the traditional rod pumping unit. And it also makes the oil produced in a safe and environmental friendly way.
文摘The global energy market is volatile at present.It is of great significance for the BRICS countries,representatives of emerging economies and energy powers in the world,to deepen practical cooperation in energy.With a large energy volume and obvious complementary advantages in energy resources,industries and technologies,the BRICS countries have a good basis and prospects for cooperation.With the continuous deepening of the BRICS cooperation mechanism,the mechanism for BRICS cooperation in energy has further improved and the path has become clear.In this paper,the history of BRICS energy cooperation mechanism,as well as the status quo and characteristics of BRICS energy cooperation are presented.From both internal and external dimensions,an in-depth analysis of the opportunities and challenges in energy cooperation among BRICS countries under the complex international situation is made,and strategic recommendations in four aspects are provided:to strengthen diversified cooperation and strategic alignment,to intensify information sharing and policy coordination,to improve financial security and settlement systems,and to promote the construction of“BRICS+”and cooperation mechanisms.
