基于海岛直流纳电网波浪能发电场关键技术研究

发布时间：2019-03-08 16:34

【摘要】：我国海域波浪能流密度较低,将使波浪能发电成本较大,其应用场合首选用电成本高昂的岛礁和海上仪器等。偏远岛礁和海上仪器等海上孤立用户缺乏土地资源,处于海洋特殊环境,难于发展太阳能、风能和生物质能等其他可再生能源,其能源解决方案首选海洋波浪能。因此,波能装置为海上孤立用户供电是双向选择的结果。综合考虑波浪资源、海洋工程和运行维护等因素,单体波能装置供电能力是有限的。为了满足日益增长的海上孤立用户用电需求,投放波能装置群,建立波浪能发电场是有效途径之一。波浪运动具有往复特性,波能装置输出功率波动较大。海岛等孤立用户微电网体量十分微小,抵抗电源冲击能力十分有限。因此,波能装置群的并网接入方式、波浪能发电场稳定供电方式、波能装置发电系统特性、馈网变换器及其控制策略和波能装置监控等都是建立波浪能发电场急需解决的关键技术。波能装置发电系统特性是研究波浪能发电场并网接入方式和波能装置馈网变换器的基础。通过建模、推理、仿真和实验等研究方法,取得了波能装置液压发电系统电阻负载模式和电压负载模式的特性公式,通过分析得出液压发电系统具有“电流源”特性,并据此提出直流纳电网技术。直流纳电网是在交流微电网结构中,由部分发电设备采用直流方式并网,与储能设备和直流用户等共同组成的相对独立的更小一级的直流电网。在波浪能直流纳电网中,波能装置群采用直流接入方式,实现海底电缆直流输电和海上可靠并联;蓄电池组提供直流母线,吸收波能装置群的功率波动;纳电网逆变器向海岛微电网供电,提供稳定可调度的电力。此外,直流纳电网技术方案使波浪能发电电力变换环节减少,使延迟消耗电力的路由效率提高10%以上。虽然液压发电系统通过不控整流可以直接并入直流纳电网,稳定可靠,但是液压发电系统的转速不可调节、液压发电系统配置不灵活等。引入交错并联BOOST馈网变换器,通过建模和推理,建立了液压发电系统转速闭环控制结构,实现了转速控制。从液压发电系统的输出功率与转速成正比的特性推出,液压发电系统没有最大输出功率。提出液压发电系统馈网变换器采用最大效率转化控制策略。通过实验训练方法取得液压发电系统最佳压力——转速曲线,馈网变换器控制液压发电系统在每个完整发电周期都工作在最佳压力——转速曲线,最终实现最大效率转化控制。此外,针对馈网变换器相控整流的缺陷,引入了PWM高频整流馈网变换器。建立了液压发电系统PWM高频整流数学模型和转速外环定子电流内环控制系统,波能装置馈网变换器同时实现了柔性整流和最高效率效率转化。最后,采用冗余设计方法,针对波能装置监控系统的特定任务和特殊要求,完成了多台波能装置监控系统的设计与实现。直流纳电网的仿真结果和DWS波浪能发电场初步运行实例证明,直流侧纳电网的功率波动不影响交流侧微电网稳定运行,交流侧微电网故障也不影响直流侧纳电网可再生能源的正常发电,这点对波浪能装置群是非常重要的,因为液压发电系统不能空载运行。直流纳电网能解决波能装置群能源合并和在微电网中稳定供电的难题,同时满足波能装置馈网变换器高可靠性的要求。仿真结果表明,交错并联BOOST变换器和PWM高频整流器都实现了馈网变换器对波能装置液压发发电系统转速的控制,最终实现最高效率转化控制。此外,PWM高频整流还实现了液压发电系统的柔性整流,输出高品质电能。多台波能装置监控系统运行结果表明,本文的波能装置监控系统针对性强,设计完善,功能全面,性能可靠。因此,本文的研究成果在波浪能发电场直流纳电网研建中将发挥重要作用,对提高波能装置能量转化总效率、提高波能装置技术成熟度和波浪能开发应用具有重要意义。
[Abstract]:The current density of wave energy in the sea area of our country is low, which will make the wave energy generate more cost. The marine isolated users such as remote island reefs and offshore instruments lack land resources, are in a special environment of the ocean, and are difficult to develop other renewable energy sources such as solar energy, wind energy and biomass energy, and the energy solution is the preferred marine wave energy. Therefore, the wave energy device is the result of two-way selection for the power supply of the isolated user at sea. Considering the factors such as wave resources, ocean engineering and operation and maintenance, the power supply capacity of the single wave energy device is limited. In order to meet the increasing demand of power consumption of isolated users at sea, a group of wave energy devices is put in, which is one of the effective ways to set up wave energy. The wave motion has a reciprocating characteristic, and the output power of the wave energy device fluctuates greatly. The island and other isolated user micro-power grid is very small, and the resistance to the power supply is very limited. Therefore, the network access mode of the wave energy device group, the wave energy transmission electric field stable power supply mode, the wave energy device power generation system characteristic, the feed network converter, the control strategy and the wave energy device monitoring and the like are the key techniques for establishing the wave energy transmission electric field. The characteristics of the power generation system of the wave energy device are the basis for studying the grid-connected access mode of the wave energy transmission electric field and the wave energy device feed-in converter. Through the research methods of modeling, reasoning, simulation and experiment, the characteristic formula of the resistance load mode and the voltage load mode of the hydraulic power generation system of the wave energy device is obtained, and the "current source" characteristic of the hydraulic power generation system is obtained through the analysis, and the direct current system technology is proposed accordingly. The direct-current nano-power grid is a relatively independent and smaller-level direct-current network which is connected in a direct-current mode by a part of the power generation equipment in an alternating-current micro-power grid structure, and is composed of an energy storage device and a direct-current user and the like. in that wave energy direct current nano power network, the wave energy device group adopt a direct current access mode to realize the direct current transmission of the submarine cable and the reliable parallel at sea; the storage battery pack provides a direct current bus, and the power fluctuation of the wave energy device group is absorbed; and the nano-grid inverter supplies power to the island micro-power network, A stable and schedulable power is provided. In addition, that direct current network technology scheme reduce the power conversion link of the wave energy power generation, so that the route efficiency of the delay consume power is increased by more than 10%. Although the hydraulic power generation system can be directly integrated into the DC-DC power grid by the non-controlled rectification, it is stable and reliable, but the speed of the hydraulic power generation system is not adjustable, and the system configuration of the hydraulic power generation system is not flexible. In this paper, a staggered parallel BOOST feed-in converter is introduced, and a closed-loop control structure of the rotating speed of the hydraulic power generation system is established by modeling and reasoning, and the rotation speed control is realized. The hydraulic power generation system has no maximum output power from the characteristic that the output power of the hydraulic power generation system is directly proportional to the rotational speed. The maximum efficiency conversion control strategy for the feed-in converter of the hydraulic power generation system is proposed. The optimal pressure _ speed curve of the hydraulic power generation system is obtained by the experimental training method, and the feed net converter controls the hydraulic power generation system to work at the optimal pressure _ speed curve for each complete power generation cycle, and finally the maximum efficiency conversion control is realized. In addition, the PWM high-frequency rectification feed-in converter is introduced for the defect of phase-controlled rectification of the feed-in converter. The mathematical model of the PWM high-frequency rectification of the hydraulic power generation system and the inner loop control system of the stator current of the rotating speed outer ring are established, and the energy-feed converter of the wave energy device simultaneously realizes the conversion of the flexible rectification and the maximum efficiency. In the end, the design and implementation of the monitoring system of multiple wave energy devices is completed by using the redundant design method, aiming at the specific tasks and special requirements of the wave energy device monitoring system. The simulation results of the direct current system and the preliminary operation examples of the DWS wave energy transmission electric field show that the power fluctuation of the direct current side power grid does not affect the stable operation of the AC side micro power grid, the fault of the alternating current side micro power grid does not affect the normal power generation of the renewable energy of the direct current side nano power grid, This is of great importance to the wave energy device group because the hydraulic power generation system cannot be run at no load. The DC-DC network can solve the problem of the energy combination of the wave energy device group and the stable power supply in the micro-power grid, and simultaneously meet the requirements of high reliability of the wave energy device feed-in converter. The simulation results show that the staggered parallel BOOST converter and the PWM high-frequency rectifier realize the control of the rotating speed of the power generation system of the wave energy device by the feed-in converter, and finally realize the highest efficiency conversion control. In addition, the PWM high-frequency rectification also realizes the flexible rectification of the hydraulic power generation system and outputs high-quality electric energy. The operation results of the monitoring system of multiple wave energy devices show that the monitoring system of the wave energy device in this paper is strong in pertinence, perfect in design, complete in function and reliable in performance. Therefore, the research results in this paper will play an important role in the research and construction of the wave energy transmission electric field, which is of great significance to the improvement of the energy conversion total efficiency of the wave energy device and the improvement of the technology maturity of the wave energy device and the application of wave energy.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P743.2

【参考文献】