考虑到功率等级和满足谐波电流限制标准,大功率家用和轻型商业变频空调的前级功率电路不再采用二极管整流器和无源滤波方式.在结合强迫整流和自然整流的基础上,提出一种采用局部PWM的三相三开关三电平AC-DC变换器的调制策略,在进行了理论分析和仿真分析后,设计了10 kW实验样机,所得结果验证了所采用的三开关局部PWM算法具有电气应力较低、转换效率较高、功率因数较高、直流电压平均值较高等优点.经过对局部PWM规律进行优化,在各种负载下,网侧电流的谐波电流含量均满足IEC61000-3-2标准.中等负载以上时输入功率因数高达0.98,效率高达0.98.%Considering the power level and in order to meet harmonic current limitation standards, the pre-stage circuit of high-power domestic variable-frequency air-conditioner and light business variable-frequency air-conditioner no longer uses diode rectifier or passive filter. Incorporating forced rectification and natural rectification, the paper presents a partial PWM modulation strategy for three-phase three-switch three-level AC-DC converter. After theoretical analysis and simulation analysis of the presented modulation strategy, a lOkW experimental prototype is designed. The experimental results prove the features of the three-switch partial PWM modulation algorithm of lower electrical stresses, higher conversion efficiency, higher power factor and higher DC average voltage. By optimizing the partial PWM principle, the harmonic components of grid side current are consistent with IEC61000 - 3 - 2 at any load, and the power factor is higher up to 0. 98, and the efficiency is higher up to 0. 98 at above medium load.
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