煤矿井下低压SVG几个关键问题

Several key issues of low-voltage SVG for coal mine

为解决煤矿井下低压配电网电能质量问题,对井下低压静止无功发生器(Static Var Generator,SVG)的几个关键问题进行了研究。选择级联H桥作为低压SVG的主电路拓扑结构,在此基础上,为使装置具备综合补偿能力,基于选择性补偿策略提出了一种同步旋转坐标变换及离散傅里叶变换(Discrete Fourier Transform,DFT)相结合的SVG指令电流检测方法,应用脉宽调制(Pulse Width Modulation,PWM)实现了指令电流跟踪控制。最后针对1 140 V装置可能存在的直流侧电容电压相内不平衡问题,提出了一种基于逆变桥自身能量平衡原理的软件均压方法。该设计方案方法简便,便于工程实现,仿真和实验验证证明了其有效性。

In order to solve the power quality problems associated with a low-voltage distribution system in coal mine,several key issues were investigated for low-voltage SVG. Cascaded H-bridge structure was chosen as the main circuit topology structure,then based on selective compensation,a reference current detection method utilizing the combination of synchronous reference frame transformation with discrete Fourier transform( DFT) was presented to realize the synthetic compensation,and the pulse width modulation( PWM) was used to realize the tracking control of instruction current. In addition,a software method was proposed to balance the capacitor voltages of 1 140 V SVG by controlling the balance of H-bridge energy. The control strategy presented in this paper was relatively simple and easy to be realized. The results of simulation and experiment show the validity of the method.