| Today,with the development of new energy,smart grids and new distributed power sources are the ideal solution to solve the problems facing energy transmission in the future,and are also the core of China’s energy structure transformation and energy conservation and emission reduction.In order to realize a smart grid,it is necessary to have enough power equipment as a support,and conventional transformers obviously do not have this kind of performance.Power electronic transformers therefore appear.And its excellent controllability and rich AC/DC interface and other advantages provide an effective energy management method for the smart grid.This paper introduces the topology classification,control algorithm and application direction of power electronic transformer(PET),and the selection of high-frequency transformer parameters in practical applications.By modeling and simulating the loss of high-frequency transformers,the change of magnetic flux loss of the three materials was obtained.It was verified that in the practical engineering applications,the loss of amorphous materials does not increase with frequency in high-frequency situations.It rises and rises,and it tends to become saturated with time,and its price is close to that of ferrite.Non-crystal is a better choice in practical applications of more than 20 k Hz.The PET DC isolation interface connects the photovoltaic system to the microgrid and studies the characteristics of the system’s overall parameters in the microgrid.First,it simulates and analyzes the output characteristics of the four parameters under normal operating conditions.It can be found through comparison.The voltage and current can be controlled to be in phase,operate in the unit power factor state,the active value is the fixed value,the reactive power is zero,the frequency is kept at 50 Hz.When the system fails,through researching its transient simulation output,it is found that the voltage and current will With slight fluctuations,the active power output is reduced,the reactive power is fluctuating,and the frequency is also fluctuating in a small range.However,they are all fluctuating in a very small range,and the fault disappears,and the system will quickly return to normal.According to the simulation results,it can be concluded that the system stability of the photovoltaic access PET isolation part in the distribution network is better.Of course,this is because the overall system capacity of the distribution network is larger,so when there is a fault,it can provide more reactive power to maintain the stability of the voltage. |
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