基于改进PWM控制的电网运行安全调制策略研究

Research on safety modulation strategy of power grid operation based on improved PWM control

为了提高电网运行抗负载扰动能力和空载能力,提出基于改进PWM控制的电网运行安全调制策略。首先,分析电网不平衡的实际情况,再采用三相PWM整流器负序电压不平衡控制策略,获取电网不对称时PWM整流器不平衡单周控制数学模型,保障电网电压滤除零序电压后的分量;利用改进功率平衡控制策略,在原有控制算法上加入负载电流前馈,解决采样延时对电流内环的响应速度造成影响导致的控制性能不佳,优化控制结果,实现电网运行安全调制。研究结果表明:所研究策略能够实现电网电压不平衡状态下的电网运行安全调制,并且具有良好的抗负载扰动能力和空载能力。

In order to improve the anti load disturbance capability and no-load capability of power grid operation,a modulation strategy of power grid operation safety based on the improved PWM control was proposed.Firstly,the actual situation of power grid imbalance was analyzed,then the control strategy for the negative sequence voltage imbalance of three-phase PWM rectifier was adopted to obtain the one cycle control mathematical model of PWM rectifier imbalance when the power grid was asymmetric,so as to ensure the component of power grid voltage after filtering the zero sequence voltage.Using the improved power balance control strategy,the load current feedforward was added to the original control algorithm to solve the poor control performance caused by the impact of sampling delay on the response speed of the current inner loop and optimize the control results,so as to realize the safe modulation of power grid operation.The results showed that the proposed strategy could realize the safe modulation of power grid operation under the unbalanced voltage,and had good anti load disturbance capability and no-load capability.