| With the rapid development of power electronic devices, high-precision high-speed computing chip, real-time simulation and control technology, various types of power electronic devices are widely used in AC-DC adjustable power supply, power supply systems, electrical transmission control and electrochemical production etc, but most power electronic devices connected to the grid through the converter, there is always the low power factor and high harmonics problem of the input current.Working principle of single phase three-level PWM rectifier is discussed and a mathematic model of the PWM rectifier is set up. Several current control principles is analyzed, include hysteresis current control, transient current control, predictive control and current decoupled control. Besides, the PWM technology and the SVPWM technology is introduced. Then, the simulation model for an application example is designed in Matlab/Simulink environment. The theories of transient current control, predictive control and current decoupled control is verified.To study harmonic characteristics of the AC-side current, the lower order harmonic characteristics of the AC-side current is derived and analyzed theoretically, respectively. The low order harmonic elimination schemes is shown, which is verified by computer simulation, respectively. Besides, the neutral point voltage affected by the rectifier work mode is analyzed for single phase three-level PWM rectifier. Then, the balance control method is proposed and verified by computer simulation. |
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