基于能量流动双PWM协调控制

Double PWM Coordinated Control Based on Energy Mathematic Model

摘要:

基于双PWM结构,根据系统能量流动分析系统在能量平衡状态和能量不平衡状态下系统各部分间的能量关系,并建立双PWM结构能量数学模型；针对系统输出能量与消耗能量不平衡时造成的直流母线电压波动以及输出功率不匹配的问题,建立关于直流母线电压以及网侧电流d轴分量的约束条件,保证系统能量能够平滑变化；采用约束条件对整流器电压外环以及功率内环进行修正,用以实现整流侧输出能量与逆变侧消耗能量的快速平衡,达到双PWM结构间协调控制的目的；根据仿真结果表明,系统在电机功率突变时,能够实现能量的快速平衡,并且能够减少直流母线电压波动,减少网侧谐波分量和直流侧电容。

Abstract:

Based on double PWM structure, analyses each part of system energy relationship on the basis of system energy flow theory when system in the energy balance state and unbalance state and build energy mathematic model of double PWM. In order to solve the problem that the DC bus voltage fluctuation and the system output power not matches the system input power dues to the system output energy not matches the system input energy, build constraint condition of DC bus voltage fluctuation and grid-side current component in the d axis. The condition can ensure the system energy smoothly varies. Using constraint condition to correct voltage outer loop and power inter loop, realize the output energy of rectifier side can fast match with the loss energy of inverter side. So the double PWM structure can ensure each part coordinated control of system. According to results of simulation, the system can realize system energy fast in balanced state and reduce DC bus voltage fluctuation when the power of load motor suddenly varies. This method also can reduce the harmonic current and capacity of the DC side capacitors.