| The heavy use of traditional fossil fuels has caused serious environmental pollution,many countries have introduced policies to encourage the use of non-polluting new energy.The electric car has obtained rapid development in China.As pure electric vehicles do not exhaust any gas,and has the characteristics of peak shaving which improve the utilization of energy.Under these circumstances,the pure electric car is promoted very quickly in recent years.With the explosion of electric vehicles,The problem of charging must be solved first.The state has introduced some relevant policies to build a large number of charging stations,resulting in harmonic effects on the power system.The paper firstly inroduces the structure and operation mode of Charging station,then inroduces the classification of charging piles and charging modes of electric vehicles.The harmonic current characteristics of Charger were analyzed from the angle of theory.The paper solves the problem that calculating harmonic expectation of charging station and estimates to the harmonic content of the charging station through the theory of Monte Carlo.According to the classification of the charger and theoretical analysis,non-vehicular and on-board charger simulation model of EV in PSCAD.Taking the 6-pulse rectifier charger as an example,the harmonic characteristics of the a single non-car charger were studied,and relationship between the harmonic content of the charging station and the number of chargers was analyzed.Then the harmonic influence of the commonly used APFC car charger was simulated and analyzed.Based on the study of the harmonic current of the charging station,the harmonic suppression method in charge was analyzed.From the different viewpoints of active control and passive control,the harmonic suppression methods include increasing pulse number,using PWM rectifier,adding passive filtering and adding active filter were studied.The harmonic source characteristics of the charger were closer to the harmonic current source.Then the paper compares the difference of that compensating the harmonics of the harmonic current source by SAPF and PAPF,then thePAPF is selected to suppress charging station harmonics.Different current control strategies--hysteresis control and SVPWM control was used and the compensation performance of different control strategies are compared.Through the comprehensive analysis,the paper compares these methods of harmonic suppression,and the test of simulation experiment was carried out.. |
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