Electromagnetic Transient Simulation Method For Converters Based On Field Programmable Gate Array

In the context of global warming,increasing extreme weather,excessive energy consumption and depletion of resources,establishing a clean,low-carbon,safe and efficient power system and continuously improving the penetration rate of renewable energy is a major strategic direction for the development of China’s power system.However,the output of renewable energy such as wind power and photovoltaics has great intermittency,randomness and fluctuation,which poses a huge challenge to the safe and stable operation of the power system.Various types of power electronic equipment represented by converters are an indispensable part of the grid connection of new renewable energy.Consequently the promotion of renewable energy and the development of technologies such as flexible DC transmission have promoted the widespread application of power electronics technology in the power grid.The introduction of a large number of power electronic equipment has brought profound changes to the operation characteristics of the power grid,and put forward higher requirements for simulation technology.On the one hand,components with greatly different dynamic characteristics,such as converters,distributed power sources,control devices,and energy storage devices,increase the nonlinear and discrete characteristics of the system,which greatly increases the complexity of the simulation.Thus more efficient and accurate modeling methods need to be studied.On the other hand,the high-frequency transient characteristics of power electronic switching devices in converters whose working states change rapidly put forward extremely high requirements on the computational efficiency of the simulation algorithm and the computational performance of the simulation platform.Therefore researching real-time electromagnetic transient simulation platform with independent intellectual property rights is of great significance for designing and testing new electrical equipment,analyzing equipment safety restrictions and protection measures,and researching and verifying optimal control strategies.In view of the above problems,this paper studies the electromagnetic transient simulation modeling,algorithm and hardware implementation of converters.The main contents are as follows:(1)A high-efficiency modeling method for electromagnetic transient simulation of converters is studied.Based on the proposed electromagnetic transient simulation theory,a basic model of the converter control system and electrical switch devices suitable for high-efficiency simulation is established.Different modeling methods of power electronic devices are analyzed,and the model of power electronic switch devices is selected comprehensively considering model characteristics and simulation scene requirements.The simulation results under several modeling methods are compared,and the accuracy of the power electronic device model adopted in this paper is verified.(2)An improved algorithm for electromagnetic transient simulation of converter based on FPGA is proposed.On the one hand,the serial characteristics in the calculation process of the existing electromagnetic transient simulation program are analyzed,and a parallel optimization algorithm is proposed to effectively compress the simulation calculation process and improve the parallel performance of the simulation.On the other hand,the timing error in the multi-rate decoupling calculation process of the converter control system is analyzed,and an improved linear extrapolation algorithm based on the Lagrange interpolation is proposed for error compensation,which improves the accuracy of the multi-rate decoupling parallel simulation.Based on the three-phase bridge inverter model,the algorithm in this paper,the existing method and the results of PSCAD simulation are analyzed and compared,which proves that the simulation method proposed in this paper has higher accuracy.(3)A highly parallel real-time simulation hardware design based on FPGA hardware acceleration is proposed.A real-time simulation hardware design architecture based on FPGA for hardware-accelerated computing is adopted,which achieves cross-platform co-simulation between FPGA and host computer.The modules inside the FPGA and the cooperative operation mode between the modules are designed,and the hardware implementation scheme of each calculation process is proposed based on the parallel optimization algorithm.A parallel grid-connected model of two-stage photovoltaic converters is built to verify the correctness and real-time performance of the proposed simulation method,and the advantages of the proposed hardware design method in balancing computational efficiency and logic resource consumption are proved.