柔性直流双向变换器及其控制策略研究

Research on Flexible DC Bi-Directional Converter and Its Control Strategy

研制了一种柔性直流配电储能式双向DC-DC变换器,在直流母线和储能装置间建立双向功率通道,以解决配电网母线电压波动大的问题。设计两相Buck-Boost交错并联结构,采用新型数字式精确恒压、恒流、恒功率控制策略,提高了变换器输出侧频率和稳态特性。试验表明,双向变换器在不同工作模式下均能正常工作,并可实现工作模式灵活切换以及自动恒压、恒流功能,通过对交错并联电感电流的均衡控制,保证了变换器高效大功率和低纹波的输出,在实际配电系统实验中验证了该变换器可靠性。

A bi-directional DC-DC converter is developed which establishes a high-power transmission channel between the DC bus and the energy storage device for flexible DC power distribution system to solve the problem that large voltage fluctuation of the DC bus.A two-phase interleaved parallel structure Buck-Boost circuit is devised and a new digital precise control strategy of constant voltage,constant current and constant power is adopted to improve the frequency and steady-state characteristics of the output side of the converter.The test results show that the bi-directional converter proper function in different working modes,it can also realize flexible switching of working modes and automatic constant voltage and constant current functions.In addition,the current balance control of interleaved and parallel inductance is realized,which ensures the high efficiency,high power and low ripple output of the converter.Finally,the reliability of the converter has been verified in actual power distribution experiments.