电压型PWM串级调速系统控制策略的研究

Research on control strategy of voltage type PWM cascade speed system

针对传统串级调速系统谐波污染严重、功率因数低等固有的缺点,设计了基于PWM逆变器的电压型串级调速系统。对幽坐标系下PWM逆变器的数学模型进行详细推导。为消除系统的耦合性和非线性选用精确线性化解耦附加变结构的控制策略,并对控制规律的构建过程加以推导。加上斩波电路的IGBT选用的转速电流双闭环PI控制,得到系统的控制图。最后利用MATLAB对控制策略的有效性进行仿真,结果表明系统不仅能够实现平滑无极调速,而且提高了功率因数、滤除了谐波、节约了能源。

Aiming at the inherent disadvantages of traditional cascade speed regulation system such as serious harmonic pollution and low power factor,a voltage cascade speed regulation system based on PWM inverter was designed.The mathematical model of PWM inverter in dq coordinates was derived in detail.In order to eliminate the coupling and nonlinear,the exact linearization decoupling additional variable structure control strategy was adopted,and the construction of control law was deduced.And the speed current double closed loop PI control was used by the IGBT chopper circuit to get the control chart of the system.Finally the effectiveness of control strategy was simulated by MATLAB.The results proved that the control strategy not only could achieve smooth and stepless speed regulation,but also could achieve the purpose of improving power factor,eliminating harmonic and saving energy.