矿用统一电能质量调节器控制策略研究

Research on control strategy of mine-used unified power quality conditioner

针对传统的矿用统一电能质量调节器在跟踪补偿电流和电压时存在开关损耗大、相间干扰严重和直流侧电压利用率低的问题,提出了一种基于空间电压矢量的恒频双滞环控制策略。通过跟踪分析单相电流、电压滞环得到固定开关频率时滞环宽度与网侧电压的函数关系,然后根据网侧电压的变化动态调节双滞环宽度,以保证开关频率的恒定,实现在跟踪补偿电流、电压的同时有效减小开关损耗;将恒频双滞环控制与空间电压矢量相结合,可以消除相间干扰,提高电压利用率,在保证电流响应速度的同时,减小电流谐波。仿真结果表明,在电压跌落和电流波形发生畸变时,采用该控制策略的电能质量调节器能够及时有效地对电网电压、电流进行补偿,补偿后的电压、电流谐波畸变率较低,保证了煤矿电网的安全运行。

In view of problems of high switching loss,serious interphase interference and low DC side voltage utilization in tracking compensation current and voltage of traditional mine-used unified power quality conditioner,a constant frequency double hysteresis control strategy based on space voltage vector was proposed.Through the tracking analysis of single-phase current and voltage hysteresis loop,the function relation between the width of time delay loop with fixed switching frequency and the voltage on the grid side is obtained.Then,the width of double hysteresis loop is dynamically adjusted according to change of the grid-side voltage to ensure the constant switching frequency,which can effectively reduce switching loss while tracking compensation current and voltage.Combination of constant frequency double hysteresis loop control and space voltage vector can eliminate phase interference and improve voltage utilization rate,and can reduce current harmonics while ensuring current response speed.The simulation results show that the power quality conditioner adopting this control strategy can compensate grid voltage and current in time and effectively when voltage sag and current waveform are distorted,and the harmonic distortion rate of voltage and current after compensation is low,which ensures safe operation of coal mine power grid.