| With the rapid development of the computer industry and the"Internet plus" concept,the power supply technology of data room has become one of the most important research topic,High reliability and high power density are the advantages of the high voltage DC power supply.As the core equipment of high voltage DC power supply system,VIENNA rectifier has become a hot research topic at domestic and abroad.The research on control strategy of VIENNA rectifier contributes to promote the production and application of high voltage DC power supply system.The working principle of VIENNA rectifier is discussed in detail.The various control strategies and pulse width modulation strategies are compared and the mathematical model of VIENNA rectifier in the three-phase static coordinate system is established.The double closed-loop control system structure of VIENNA rectifier is designed.The PI control strategy is adopted to the voltage loop and quasi proportional resonant control is adopted to the current loop to overcome the problem of slow response speed by repetitive control.The parameters of the controller is optimized and designed in theory to realize the function of unit power factor rectifier primely.Aiming at the problem that the current in the zero crossing distortion,the duty ratio feedforward control is introduced to the control system and the expression of duty ratio feedforward is derived.Aiming at the problem that the grid side current harmonic caused by the power grid voltage distortion.The multi proportional resonant control that contained the main harmonic component is adopted to the current loop and the compensation control of harmonic current is added to significantly improve the sinusoidal of network side currentAiming at the problem of midpoint potential imbalance in VIENNA rectifier,the zero sequence of neutral point potential balance control is added to output of three-phase voltage loop.According to the characteristics that the unbalanced output of DC voltage midpoint has the cyclical fluctuations,the zero sequence component is added to the proportion resonant control to solve the neutral point voltage deviation.Compared with traditional proportional control,the steady-state component is smaller.According to the VIENNA rectifier(6kW,three-phase 380V input,750V output),the main circuit parameters are designed,the PSIM simulation model and the corresponding experimental system are developed to verify the control strategy.Both the simulation and experiment results show that the proposed control strategy can effectively improve the quality of input current waveform and enhance the anti disturbance ability of output voltage and inhibit the unbalance of neutral point potential. |
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